concurring in part and dissenting in part:
This appeal arises from actions for breach of a lease filed by the landlord against over sixty individuals who were members of three different tenant law firms which occupied the leased premises in the District of Columbia. The principal question presented on appeal is whether the trial court properly dismissed the landlord’s actions on the ground that they are barred under principles of res judi-cata and collateral estoppel by the final order of the Pennsylvania Supreme Court in a probate proceeding distributing the estate of Harold R. Schmidt, one member of the law firm tenants that succeeded the original tenant. The order in that Pennsylvania probate case, adjudicated in the context of a single defendant’s estate, is erected by the majority as a bar to the landlord’s claims against approximately fifty of the named defendants who, like Schmidt, also were members of law firm tenants that succeeded the original tenant. The majority reasons that the landlord’s claim against Schmidt’s partners is precluded because it is the same claim that was rejected in the Schmidt estate proceeding and the landlord had a “full and fair” opportunity in that proceeding to litigate the merits of its claim. I submit this conclusion is incorrect. Proper application of claim preclusion principles requires that we first ascertain whether the basis for the final order in Pennsylvania is one applicable to Schmidt’s partners. In other words, there is no res judicata bar unless Schmidt’s partners are in privity with Schmidt with respect to the matter previously decided. Here, we *1078have no assurance that that is the ease because the Pennsylvania Supreme Court did not express any opinion at all. Thus, we do not know whether its judgment in favor of the Schmidt estate was on a basis shared by Schmidt’s partners or, rather, for reasons specific to Pennsylvania probate law which are inapplicable in the present action to Schmidt’s partners.
The majority’s sweeping application of res judicata in this ease has consequences out of proportion to the limited action taken by the landlord in the Pennsylvania estate proceeding, and enforces what is essentially a default judgment entered in a probate proceeding for the purpose of adjudicating claims against only the Schmidt estate, one of the more than sixty defendants in the present litigation. Precluding the present litigation in this context does not serve the purposes of res judicata, to avoid multiplicitous and vexatious litigation and conserve judicial resources, for here the landlord had proceeded in a straightforward and efficient manner, by filing actions involving all relevant parties in Superior Court, which has authority to adjudicate the landlord’s claims against all the defendants.
The substantive issue in the present case is whether the individual tenants are liable to the landlord under the lease. Resolution of that issue may have been, but need not have been, the basis for the Pennsylvania Supreme Court’s final order in the probate proceeding. I conclude that because “the thing decided” in the Pennsylvania proceeding may well have been different from the issue presented for adjudication in the landlord’s present action in the District of Columbia against Schmidt’s partners, we are consequently unable to determine whether they are Schmidt’s privies. Given this uncertainty, Pennsylvania law prohibits application of either res judicata or collateral estoppel. As to all the defendants but Schmidt, therefore, I would reverse and remand for consideration of the landlord’s claims on the merits.1
By statute, all courts in the United States must give the judicial proceedings of any state “the same full faith and credit ... they have by law or usage in the courts of such State.” 28 U.S.C. § 1738 para. 3 (1994).2 Therefore, we look to the law of Pennsylvania to determine the effect of the Pennsylvania courts’ orders on the actions filed in the District of Columbia.3
The Pennsylvania Supreme Court has explained the policy and purpose underlying res judicata:
The doctrine of res judicata is based on public policy and seeks to prevent an individual from being vexed twice for the same cause ... As pertinently stated in Hochman v. Mortgage Fin. Corp., 289 Pa. 260, 263, 137 A. 252, 253 (1927): ‘The rule should not be defeated by minor differences of form, parties or allegations, when these are contrived only to obscure the real purpose, a second trial on the same cause between the same parties. The thing which the court will consider is whether the ultimate and controlling issues have been decided in a prior proceeding in which the present parties actually had an opportunity to appear and assert their rights. If this be the fact, then the matter ought not to be litigated again, nor should the parties, by a shuffling of plaintiffs on the record, or by change in the character of the relief sought, be permitted to nullify the rule.’
*1079Stevenson v. Silverman, 417 Pa. 187, 208 A.2d 786, 788 (1965).
Under Pennsylvania law res judicata and collateral estoppel apply only if certain conditions are met:
It is well settled that for the doctrine of res judicata to prevail there must be a concurrence of four conditions: 1) identity of issues, 2) identity of causes of action, 3) identity of persons and parties to the action, and 4) identity of the quality or capacity of the parties suing or being sued. With respect to collateral estoppel we have recently stated that a plea of collateral estoppel is valid if, 1) the issue decided in the prior adjudication was identical with the one presented in the later action, 2) there was a final judgment on the merits, 3) the party against whom the plea is asserted was a party or in privity with a party to the prior adjudication, and 4) the party against whom it is asserted has had a full and fair opportunity to litigate the issue in question in a prior action. Thus, for [a party] to invoke either res judicata or collateral estoppel the issues presented before [the first court] must be the same as those raised in the instant action.
Safeguard Mut. Ins. Co. v. Williams, 463 Pa. 567, 345 A.2d 664, 668 (1975) (citations omitted); accord, e.g., Mintz v. Carlton House Partners, Ltd., 407 Pa.Super. 464, 595 A.2d 1240, 1246 (1991). Pennsylvania law also provides that, in considering whether a prior adjudication is res judicata, a court must look to the judgment of the highest court deciding the issue. See Speyer, Inc. v. Goodyear Tire and Rubber Co., 222 Pa.Super. 261, 295 A.2d 143, 146 (1972). In this case, that is the Pennsylvania Supreme Court.
Applying the above principles to the landlord’s claim against the Schmidt estate, res judicata applies to bar the claim filed in Superior Court if it was or could have been brought against the estate in the probate proceeding. See Stevenson, supra, 208 A.2d at 788; Restatement (Second) of Judgments § 19 cmt. a. Thus, claim preclusion bars the landlord’s present claim against the Schmidt estate. Claim preclusion does not directly apply to bar the landlord’s claims against Schmidt’s partners, however, because those claims not only were not brought against Schmidt’s partners, but they could not have been brought against the partners in the context of a probate proceeding to distribute the Schmidt estate. The majority reasons that the landlord’s claims against Schmidt’s partners are barred under principles of claim preclusion, not collateral estop-pel, because the partners are in privity with Schmidt—in essence arguing that they are the “same party” for claim preclusion purposes. Before that indirect application of claim preclusion can be accomplished, however, it must first be determined whether the “issue decided” in the Pennsylvania adjudication is one as to which Schmidt’s partners in the instant litigation can claim to be in privity with the Schmidt estate.4 With respect to application of res judicata to bar the landlord’s claims against Schmidt’s partners, therefore, our primary question is whether the issue decided by the Pennsylvania Supreme Court in the probate action concern*1080ing the Schmidt estate was the same or different from the issue presented to the Superior Court of the District of Columbia with respect to Schmidt’s partners. Therefore, in this context, the difference between claim preclusion and collateral estoppel is a distinction without much practical difference.
The cause of action filed in the District of Columbia was for breach of a lease contract. The issues to be resolved in that case are whether some or all of the partners of the various firms and their successors that occupied the landlord’s premises after the original tenant are liable under the landlord’s lease with the original tenant and, if so, in what amount. The action filed by the landlord in Pennsylvania that is claimed to bar the present suit was to protect the landlord’s lease claim against the Schmidt estate, in the context of a probate proceeding. Specifically, triggered by Schmidt’s death and the start of probate proceedings in Pennsylvania, one week before filing the present action in Superior Court the landlord filed a notice of its claim against real property of the estate within the statutorily prescribed period.5 The landlord then sought to defer distribution of the Schmidt estate’s assets until after the lease claim against Schmidt and the other defendants was resolved in one of two actions that already had been filed for that purpose and which involved all the relevant parties: either in the present action filed in the District of Columbia by the landlord or in the declaratory judgment action filed by the survivor firm in Pennsylvania state court in Pittsburgh, later removed to the federal district court. The Pennsylvania courts rejected the landlord’s request to defer distribution of the estate.6 Before we can compare the issues in the present case with those decided in the Pennsylvania litigation to determine whether they are the same, it is necessary first to describe the law regarding distribution of the assets of an estate in Pennsylvania.
In Pennsylvania, an estate may be distributed in two ways: An “at-risk” distribution without an accounting and audit and a distribution after an accounting and audit. See 20 Pa. Cons.Stat. Ann. §§ 3532, 3533 (1975). After an at-risk distribution has been made, a claimant loses his claim unless he files a timely written notice of claim. Id. § 3532(a). Once distribution is made in conformity with a final decree following an accounting and audit, the personal representative has no liability for claims against the estate. Id. §§ 3386, 3533.7
If those were the only rules, then it would appear that the only way that a claimant could recover on a claim if an executor has filed an accounting, as was the case here, is to object and present the claim for adjudication prior to final audit. See id. § 3386 (providing that any claim not admitted by the personal representative or presented by the claimant at an audit cannot be satisfied out of the distributed assets). However, where the claim already has been submitted to another court, as also was the case here, Pennsylvania law permits the probate court, in its *1081discretion, to delay all or part of a distribution pending the result in the other litigation:
When any clahn not proved in the orphans’ court division is being litigated in any other division or court, State or Federal, having jurisdiction thereof, the court may make such provision for the distribution or satisfaction of the claim as shall be equitable.
Id. § 3389 (emphasis added).
In In re Estate of Mellon, the Pennsylvania Supreme Court listed some of the factors the probate court should consider in deciding whether to delay distribution pending the outcome of litigation in another court:
(1) the nature of the claim being asserted before the other tribunal, (2) the hardship, if any, which deferred distribution of principal or income would impose on the estate or the individual or charitable beneficiaries, and (3) the adverse effect of refusing any withholding and thereby precluding satisfaction from estate assets of a possibly meritorious claim being adjudicated in another court.
455 Pa. 294, 314 A.2d 500, 503 (1974).
The court also noted that the commissioner’s comment to section 3389 states that the section
“gives the orphans’ court the opportunity in its discretion to postpone final distribution where advisable or to make final distribution where the claim, in justice to other interested persons, should be presented in the orphans’ court. The court, in addition to using its discretion as to whether any fund will be withheld, will exercise a[sic] discretion as to the amount to be withheld.”
Id. (emphasis added).
Turning to the case at hand, the landlord, in its presentations to the probate court, clearly requested only that final distribution be stayed pending conclusion of the litigation in either the survivor firm’s declaratory judgment action in Pennsylvania or in its own action which had previously been filed in the District of Columbia. In the landlord’s “Statement of Objections to Account,” filed January 5, 1990, it noted the pendency of its action in the District of Columbia and requested that the at-risk distributions already made “be returned to the estate ... pending resolution of the claim ... against the estate.” The statement did not attempt to state in any way the merits of the landlord’s claim under the lease.
The landlord’s second filing, on January 12, 1990, in response to the executrix’ accounting was even clearer. It was captioned “Petition for Continuance of Audit and Distribution of Estate Pending Resolution of Litigation Against Estate.” The landlord repeated its previous request for relief, attaching a copy of its District of Columbia complaint to the petition. Again, the landlord did not address or even mention the merits of its action in the body of its petition. Furthermore, the petition expressly cited section 3389 of the Pennsylvania Code, mentioned the pendency of both the District of Columbia action and the survivor firm’s declaratory judgment action then pending in federal court in Pittsburgh, and concluded:
Whether the District of Columbia action or the Pittsburgh action will go forward to judgment has not yet been decided; but, in whichever court the action ultimately is concluded, the issue of ... liability of decedent ... will be decided.
(Emphasis added).
Even though the landlord may not have intended to seek and, indeed, actively resisted, any adjudication in the probate court of its lease claim against the Schmidt estate, it is quite clear that the probate court did consider the landlord’s claim against the Schmidt estate on the merits, and denied the claim. After a hearing which the landlord did not attend consistent with its position that it had not filed a claim, the Pennsylvania probate judge concluded that the landlord had filed a claim, denied the landlord’s request to withdraw the claim, and after an ex parte hearing on the merits, applied District of Columbia law to deny the lease claim based on “evidence presented by the Estate, combined with the lack of any evidence whatsoever in support of [landlord’s] position.” In essence, the probate judge entered a default judgment. The probate court, sitting en banc, affirmed the probate judge’s order without an opinion.
*1082The intermediate appellate court in Pennsylvania, the Superior Court, rejected the contention that “appellant merely file[d] a request that the orphans’ court division postpone distribution pending the resolution of the District of Columbia action.” It also concluded that the probate court did not abuse its discretion by refusing the landlord’s request to withdraw its claim and that it had jurisdiction to decide the claim. The merits of the claim were not presented to the Superior Court, and it therefore did not rule on the probate court’s denial of the lease claim.
In determining whether the landlord’s present action against Schmidt’s partners is barred by the probate proceedings in Pennsylvania, we look to the “ultimate judgment” which, in this ease, was rendered by the Pennsylvania Supreme Court. See Speyer, supra, 295 A.2d at 146. The Pennsylvania Supreme Court affirmed the Superior Court’s judgment without its own opinion and without adopting any of the opinions below. One justice dissented, also without opinion. Again, we look to Pennsylvania law to interpret the Pennsylvania Supreme Court’s ruling in the Schmidt case for purposes of determining its preclusive effect on the present action. Pennsylvania law provides that “the findings of a trial court which are not relied upon on appeal should not remain res judicata.” Id. In a case involving a subsequent action against a different party, as here, the appellate court in Speyer reasoned that “it is clear that an appellate court’s refusal to rest its affirmance on a certain finding is often indicative of an infirmity in the finding” and that binding a party to a ground not relied upon on appeal would deprive the party of his statutory right to an appeal. Id.8 If the contrary rule were adopted, appellate court rulings inadvertently could make questionable lower court findings res judicata. Id.9
The Speyer court aligned itself with the majority view that “an appeal creates a clean slate, so to speak, for purposes of res judica-ta, upon which the appellate court’s grounds for decision are inscribed.” The Second Re*1083statement of Judgments10 addresses how to determine whether an issue has been decided, for preclusion purposes, in the context of appellate decisions from lower court rulings setting out different bases for decisions:
If the judgment of the court of first instance was based on a determination of two issues, either of which standing independently would be sufficient to support the result, and the appellate court upholds both of these determinations as sufficient, and accordingly affirms the judgment, the judgment is conclusive as to both determinations ....
If the appellate court upholds one of these determinations as sufficient but not the other, and accordingly affirms the judgment, the judgment is conclusive as to the first determination.
If the appellate court upholds one of these determinations as sufficient and refuses to consider whether or not the other is sufficient and accordingly affirms the judgment, the judgment is conclusive as to the first determination.
Restatement (Second) of Judgments § 27 emt. o (1982).
In the present case, we are faced not with a higher court’s rejection or refusal to consider a basis for the lower court’s ruling, but with a bare affirmance by the Pennsylvania Supreme Court, without opinion. Faced with this judicial silence, we simply do not know the basis for the Pennsylvania Supreme Court’s affirmance. The majority concludes, however, that the Supreme Court must have affirmed the substance of the lower court’s opinion, not merely its judgment. That conclusion is at odds with Pennsylvania law that an appellate court considers, and either affirms or reverses, judgments not opinions. See Hader v. Coplay Cement Mfg. Co., 410 Pa. 139, 189 A.2d 271, 274 (1963) (“Upon appellate review we are not bound by the reason or reasons advanced by the court below in support of a judgment or order for it is the judgment or order itself which is the subject of review.”). There is no indication whatsoever from the Pennsylvania Supreme Court that it intended to adopt any of the lower courts’ varying opinions. Although we know the basis for two of the lower courts’ orders, we know nothing of the reason behind the Supreme Court’s affirmance. The Orphan’s Court ruled on the merits of the claim and denied it; the Superior Court decided only that the Orphan’s Court had authority to address the landlord’s claim, but did not reach the merits of the claim. We also know that the landlord maintained at all levels up to the Supreme Court,11 that the court had discretion pursuant to § 3389 and the factors outlined in In re Estate of Mellon, supra, to either defer or allow final distribution of the estate after taking into account the pendency of the landlord’s claim in another forum. Thus, the Pennsylvania Supreme Court could have affirmed the lower court’s judgment on either the probate court’s reasoning that the lease claim was presented to it and properly denied, or on the second alternative ground, the Superior Court’s reasoning, that the probate court had jurisdiction to hear the claim on the merits but that the landlord had waived its right to present the claim on the merits, or on the third alternative ground, based on the landlord’s argument, that even if the claim was not before the probate court, it was not an abuse of discretion to refuse to further delay distribution of the Schmidt estate notwithstanding that the claim was pending in another forum.12 Any of these grounds would sustain *1084the lower court’s judgment, which was to foreclose the landlord’s claim against the Schmidt estate. “[A] correct decision will be sustained if it can be sustained for any reason whatsoever; in other words we will not reverse in such a case even though the reasons given by the court below to sustain its decision was [sic] erroneous [citing eases].” Hader, supra, 189 A.2d at 274-75 (quoting Sherwood v. Elgart, 383 Pa. 110, 117 A.2d 899, 901-02 (1955)). Of the possible grounds that could sustain the lower court’s judgment, only one would constitute a holding by the Pennsylvania Supreme Court relevant to the issue in the present action with respect to Schmidt’s partners, that the landlord’s claim under the lease was denied on the merits. See Stevenson, supra, 208 A.2d at 788 (“A final valid judgment upon the merits by a court of competent jurisdiction bars any future suit between the same parties or their privies on the same cause of action.”) (first emphasis added). Clearly, there would be no preclusive effect against Schmidt’s partners if the Pennsylvania Supreme Court had expressly ruled against the landlord’s claim, not on the merits, but because it considered that the estate should be distributed without delay. Restatement (Second) of Judgments § 51(l)(b) (1982). Simply put, unless we know that the Pennsylvania Supreme Court denied the landlord’s lease claim against Schmidt on the merits, we cannot determine whether Schmidt’s partners are privies for the purpose of applying either res judicata or collateral estoppel. The question before us is whether the “ultimate and controlling issues [in the present litigation] have been decided in a prior proceeding.” Stevenson, supra, 208 A.2d at 788.
The Pennsylvania Supreme Court has said that where the grounds for the decision asserted to have preclusive effect cannot be ascertained and it “would be pure speculation [to identify the issue decided,] ... we will not apply the doctrines of res judicata or collateral estoppel.” Safeguard Mut. Ins. Co., supra, 345 A.2d at 669-70.13 It is entirely possible, as the majority states, that the Supreme Court of Pennsylvania affirmed the lower court’s judgment- because it agreed with denial of the landlord’s claim against the Schmidt estate on the merits. It is also *1085possible, however, that it did not.14 Riding on our interpretation of that uncertainty in the Supreme Court’s affirmance in the Schmidt estate case is the viability of the landlord’s claims against fifty of Schmidt’s partners in the present action.15 The tenants have not met their burden of persuading us that the uncertainty should be resolved in their favor because they have not presented us with evidence that application of res judi-cata in this case would not be speculative. See Restatement (Second) Judgments § 27, cmt. f (1982) (“The party contending that an issue has been conclusively litigated and determined in a prior action has the burden of proving that contention.”).
I disagree with the majority’s reliance on Commonwealth v. Hilliard, 3 Pa.Cmwlth. 560, 284 A.2d 326 (1971), for the proposition that res judicata applies even though the basis for the Supreme Court’s affirmance may be unknown. As Hilliard makes clear, that holding applies as “between the parties in this case.” Id. 284 A.2d at 327. That means only that the landlord’s claim against the Schmidt estate, the same parties to the probate action, is barred. Here, however, Schmidt’s partners were not parties to the Schmidt estate proceeding. For the Schmidt estate judgment to have preclusive effect with respect to non-parties, such as Schmidt’s partners, on the ground that they are in privity, one must first determine whether claim preclusion applies because they are privies of Schmidt with reference to the litigated matter or, what amounts to the same thing in this context, whether collateral estoppel should preclude the landlord from relitigating the same issue against Schmidt’s partners that was litigated and decided in the Pennsylvania probate proceeding.
As under Pennsylvania law we are not free to speculate upon the ground on which the Pennsylvania Supreme Court may have affirmed the order of the appellate court, the statements of the various lower courts in Pennsylvania characterizing what the landlord presented to the probate court for decision and denying the landlord’s claim under the lease do not preclude the landlord’s present actions against third parties filed in the Superior Court of the District of Columbia. I would reverse and remand the trial court’s dismissal of all the claims except the one against Schmidt’s estate.
. I agree with the majority’s reasoning that collateral estoppel does not bar the landlord’s action against members of the original tenant law firm.
. The tenants and the trial court rely upon the Full Faith and Credit Section of the Constitution. U.S. Const, art. IV, § 1. That section, however, applies by its terms only to states and not to the United States or to the District of Columbia. See Mills v. Duryee, 11 U.S. (7 Cranch) 481, 485, 3 L.Ed. 411 (1813) ("The [appellant] object[s] that the act [implementing the Full Faith and Credit Section] does not apply to Courts of th[e] district [of Columbia], The words of the act afford a decisive answer, for they extend to 'every Court within the United States.’ ”).
.The issues presented by this case are quite baffling and arise in a complex factual and procedural context. Our duty to apply Pennsylvania law cautions us to decide an issue only if there is "controlling precedent” on the relevant question of law. In these circumstances, even though no party requested it, the more prudent course would have been to certify the unanswered legal questions to the Pennsylvania Supreme Court. D.C.Code § ll-723(h)(l) (1995).
. The issue here is not, as the majority posits, whether Schmidt and the other defendants are privies because they are partners. See ante at 1073. That is not in contention. The issue is whether the Pennsylvania Supreme Court decided on a basis that relates to their status as partners. See Restatement (Second) of Judgments, § 60(l)(a):
(1) A judgment in an action by an injured person against a partner upon an obligation or liability incurred in the course of partnership business:
(a) If against the injured person, terminates his claim against another partner based upon that obligation;
(Emphasis added). Comment d to § 60 elaborates that the reason for the bar against partners is that "[t]he partners stand in relation of persons vicariously responsible for each other’s conduct and the principle stated in § 51 applies.” Section 51(l)(b) provides that
If two persons have a relationship such that one of them is vicariously responsible for the conduct of the other, and an action is brought by the injured person against one of them,
(1) A judgment against the injured person that bars him from reasserting his claim against the defendant in the first action extinguishes any claim he has against the other person responsible for the conduct unless:
(b) The judgment in the first action was based on a defense that was personal to the defendant in the first action.
(Emphasis added).
. The form filed by the landlord in Pennsylvania states on its face that it "is filed under Section 732(b)(2) of the Fiduciaries Act of 1949 as amended.” That section is codified as 20 Pa. Cons.Stat. Ann. § 3532(b)(2). The particular subsection cited in the notice provides that no claim may be made against real property conveyed by the personal representative "unless [the] claimant, within one year after the decedent’s death, files a written notice of his claim with the clerk.” 20 Pa. Cons.Stat. Ann. § 3532(b)(2) (emphasis added). It appears that the Schmidt estate did not even have real properly. Thus, the notice form most likely was simply filed by diligent counsel to protect its client's potential interest in the assets of an estate within a statutory time limit.
. As discussed in detail in the majority opinion and infra, the Pennsylvania Orphan’s Court, over the landlord’s objection, did not limit itself to the requested relief to defer distribution of estate assets, but expressly addressed the merits of the landlord's claim against the Schmidt estate and denied the claim. There were three subsequent levels of review, a three-judge panel of the Orphan’s Court, the Superior Court (the intermediate appellate court) and the Pennsylvania Supreme Court. Although all three courts affirmed, only the Superior Court issued an opinion, which dealt solely with the Orphan’s Court authority to adjudicate the claim. In none of those subsequent rulings were the merits of the landlord’s claim addressed.
.For this reason the landlord’s claim against Schmidt’s estate is barred not only by res judica-ta, but also by operation of Pennsylvania probate law once distribution of the estate was made in conformity with a final decree.
. Without involving ourselves in the intricacies of Pennsylvania probate jurisdiction, it appears that the intermediate appellate court's reasoning in the present case may not be persuasive on at least one factual point. The passage addressing whether the landlord had requested a ruling on the merits of the lease claim is as follows:
[A]ppellant [did not] merely file a request that the orphans' court division postpone distribution pending the resolution of the District of Columbia action. Rather, appellant filed a claim against the Estate. Furthermore, at the time when appellant filed its claim against the Estate, no litigation was pending in the District of Columbia. For the foregoing reasons, the orphans’ court division did not abuse its discretion in concluding that appellant had presented a claim pursuant to 20 Pa.C.S.A. §§ 3386 and 3525 [sic—there is no such section] ....
The only relevant filing that the landlord had made in Pennsylvania before commencing the instant action in Superior Court in the District of Columbia was on a single page form addressed to the Clerk of the Orphans’ Court Division which had to he timely filed in order to preserve claims against real property in the Schmidt estate pursuant to § 3532(b)(2). See supra at 1081 and ante at n. 13. We note that when the U.S. District Court rejected the Schmidt estate's executrix's argument that the declaratory judgment action she had filed against the landlord should be remanded to state court, it stated—contrary to the conclusion of the Orphan’s Court and Superi- or Court—that “[a] claim pursuant to § 3532(b)(2) does not initiate a judicial proceeding, but merely preserves an asserted interest against real property.” An opinion by the Pennsylvania Supreme Court on the issue would, of course, be controlling on a question of state law over the federal court’s interpretation; but we have no such opinion here. Therefore, in the present case the conflicting opinions of the lower state courts and the federal district court on the legal consequences of the landlord's § 3532(b)(2) filing provide some reason to believe that the Pennsylvania Supreme Court’s summary affir-mance without adopting the opinion below might well be "indicative of an infirmity in the [lower court’s] finding.” Speyer, supra, 295 A.2d at 146.
. The majority clarifies that because Speyer involved a subsequent action against a non-party, the court’s use of the term res judicata refers not to claim preclusion but to collateral estoppel. As noted earlier, claim preclusion applies only to a second action between the same parties; collateral estoppel to actually litigated issues that are the same in a subsequent as in a previous action. As also noted earlier, in this case the distinction is without practical difference because in order to apply principles of claim preclusion to bar Schmidt’s partners, one must first establish that the issue previously adjudicated is one as to which Schmidt and the partners are in privity. Therefore, the Speyer ruling is applicable to this case.
.Speyer cited to the First Restatement of Judgments (1942) to the same effect:
According to the Restatement of Judgments, "Where the trial court bases [a] judgment upon two alternative grounds, and an appellate court affirms the judgment solely on one of the grounds, the judgment is not conclusive in a subsequent action in which the other ground is in issue.” Section 68, comment n (1942). To the same effect is § 69, comment b. See Scott, Collateral Estoppel by Judgment, 56 Harv. L.Rev. 1, 15 (1942). A similar rule would undoubtedly apply in the case of an appellate court's affirmance of a decision on a ground suggested by itself, after passing over the trial court’s premise.
Speyer, supra, 295 A.2d at 146.
. The record does not reveal the question presented to the Pennsylvania Supreme Court upon which it decided to grant review.
. An appellate court may affirm on a ground different from that relied upon by the lower court. See, e.g., In re Estate of Prynn, 455 Pa. 192, 315 A.2d 265, 267 & n. 9 (1974); Brew v. *1084Hastings, 206 Pa. 155, 55 A. 922, 925 (1903) ("[A]s the decree is right, the reasons work no material injury to anybody; we pass them over, therefore, as harmless, and affirm [the] decree.”). For example, the Pennsylvania Supreme Court has affirmed an order on the alternative ground that the lower court did not abuse its discretion, where, although the lower court had concluded incorrectly that it had no discretion in the matter, it had also found that the appellant had shown no legally sufficient reason for an exercise of discretion in its favor. See E.J. McAleer & Co. v. Iceland Prods., 475 Pa. 610, 381 A.2d 441, 443 & n. 4, 444 (1977). Similarly, in the present case, in striking the landlord’s withdrawal of its claim, the probate court found that the landlord’s claim should have been presented to it for trial. Under In re Estate of Mellon, supra, such a finding would justify decreeing a distribution without allowance for the landlord’s claim, thus affording alternative grounds for affirming the probate court’s judgment. The intermediate appellate court in the Schmidt probate proceeding applied the rule permitting affirmance on an alternative ground stating that ”[w]e affirm the order of the orphan’s court division rather than the opinion in support thereof."
. The majority’s attempt to distinguish Safeguard Mut. Ins. Co., supra, as involving the "opposite order of events,” ante at 1075, is unavailing. In Safeguard, the Pennsylvania Supreme Court refused to give preclusive effect to the denial of a preliminary injunction by a trial court in a prior proceeding, on a subsequent proceeding also seeking a preliminary injunction between the same parties, but on different grounds. Among other things, the court noted that because the trial court in the earlier case "did not give an opinion explaining [its] ruling” the appellant in the subsequent proceeding could not “claim that [the court] decided the case on the merits.” Id. 345 A.2d at 669. That the court in Safeguard looked at the trial court's ruling in the previous action is not a controlling difference because the trial court’s judgment appears as the only judgment in the previous action; there is no indication that a higher court affirmed. The point of Safeguard is that speculation is not permissible. Id. at 670. In this case, because the Orphan's Court judgment was appealed and eventually affirmed by the Pennsylvania Supreme Court, it is that judgment—not that of the Orphan’s Court or the Superior Court—to which we must look. Speyer, supra, 295 A.2d at 146. Therefore, as in Safeguard, where the Pennsylvania Supreme Court refused to give preclusive effect to the trial court's judgment without opinion in a previous proceeding, application of Safeguard to this case requires that we similarly refuse to give preclu-sive effect to the Pennsylvania Supreme Court’s affirmance without opinion, because to do otherwise would be to indulge in impermissible speculation.
. To bring the point closer to home, if this court were to affirm a trial court ruling without opinion, it would be pure speculation to conclude that our bare affirmance meant the trial court did not err. As is well known, we will not reverse, even if there is trial court error, unless the error has affected "substantial rights of the parties.” D.C.Code § 11—721(e) (1995).
. ”[W]hen the amount in controversy in the subsequent action far exceeds that involved in the initial action, unyielding application of estop-pel doctrine may operate unfairly against the party who is precluded from relitigating an issue.” Restatement (Second) of Judgments, Introductory Note to Title E—Issue Preclusion (1982).