dissenting.
We are a nation governed by the rule of law upon which our liberty depends. This case involves a deprivation of defendant’s liberty because of his involuntary mental commitment pursuant to ORS chapter 426.1 The majority rejects defendant’s claim that constitutional error occurred in the hearing that led to his commitment and the resulting deprivation of his liberty because of, in its view, his failure to raise a “reviewable” issue on appeal. I emphatically dissent for the reasons that follow.
An understanding of this case begins with ORS 426.100(1)(d), which provides, in relevant part, that in an involuntary mental commitment hearing, the court shall advise the allegedly mentally ill person of “[t]he right to subpoena witnesses[.]” In State v. Allison, 129 Or App 47, 49-50, 877 P2d 660 (1994), we explained the import of ORS 426.100(1):
“Involuntary commitment proceedings involve the possibility of a ‘massive curtailment of liberty’ and, thus, implicate due process protections. Vitek v. Jones, 445 US 480, 491, 100 S Ct 1254, 63 L Ed 2d 552 (1980). In Oregon, the legislature has developed the involuntary commitment procedures contained in ORS chapter 426. Those mandatory procedures are designed to ensure that all allegedly mentally ill persons get the benefit of a full and fair hearing before that person is committed. An integral part of that procedure is the advice of rights contained in ORS 426.100(1). State v. Johansen, 125 Or App 365, 370, 866 P2d 470 (1993).”
Here, the trial court, pursuant to the direction of the statute, informed defendant, an allegedly mentally ill person, during the involuntary mental commitment hearing that his counsel “could use the subpoena power, that is to say the power and process of the courts to compel the production of *22any evidence or witnesses who could speak in your favor.” Defendant then responded immediately to the court’s explanation,
“Oh, okay. I’d like my sons, both of my sons in here because they’re the only ones that live — I don’t live with these people, I don’t even see them.”2
In turn, the trial court was not taken with the request of defendant to subpoena his sons as witnesses. It said promptly, “Let me be straight with you about that, sir. * * * Your, your sons are not going to be brought into your presence.” Defendant protested, “Why, why? Because they’re my, they’re the only ones that I spend time with every day.” However, the court remained firm in its ruling; it told defendant, “I’m not going to put those children through this.”
Later, defendant’s counsel joined the request to subpoena defendant’s sons. He urged to the court:
“They [defendant’s sons] could testify by phone as he suggested earlier or anything else, but at this point we would object both on the Oregon, U.S. Constitutional (inaudible), proceeding without being able to subpoena the witnesses that he requested.”
Nevertheless, faced with multiple challenges to its ruling, the trial court concluded:
“Thank you, [defense counsel]. The Court is satisfied that, that there is substantial likelihood that the children’s evidence would not be helpful to [defendant] under these circumstances.”
On appeal, defendant contends that the trial court erred by denying him “the opportunity to subpoena witnesses for the hearing,” relying on his due process right to have a fair hearing. The majority refuses to review defendant’s claim of error on several grounds. Unlike the majority, I believe that the record adequately presents a reviewable issue and that it demonstrates that a violation of due process occurred when the trial court refused to permit defendant to *23subpoena witnesses who could give testimony relevant to the grounds for commitment.
The proper analysis is straightforward. Defendant was advised by the trial court of his right to subpoena witnesses in accordance with ORS 426.100(1)(d). He invoked that right, but the trial court refused to permit him to exercise it. In light of the above record, whatever discretion the trial court could exercise in making its ruling necessarily exceeded permissible bounds. Due process entitled defendant to a fair hearing. Under the facts of this case, that means that he was entitled to subpoena witnesses who could give testimony relevant to whether he was dangerous to himself or unable to care for his own personal basic needs. “ ‘Relevant evidence’ means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” OEC 401 (emphasis added). Defendant told the court that he wanted to call his sons as witnesses because they were the only ones who lived with him. The relevance of the sons’ testimony is self-evident; those persons who live with defendant and/or are aware of his living conditions are the persons most likely to be able to testify about whether defendant was dangerous to himself or unable to care for his own personal basic needs. Thus, the trial court’s refusal to permit defendant to subpoena his sons as witnesses for the commitment hearing was procedural error, and it operated to deny defendant due process of law.
In contrast, the trial court appeared to base its ruling on the fact that defendant proposed to call his children as witnesses as opposed to calling other witnesses who do not have that particular relationship. The record does not tell us the ages of defendants’ sons, nor does it appear from the record that the trial court was aware of that information.3 They could be adults or minors. Under Oregon law, “any person who, having organs of sense can perceive, and perceiving can make known the perception to others, may be a witness.” OEC 601. It would be pure speculation to conclude on this record that defendant’s sons were not competent witnesses. Moreover, even if defendant’s sons are minors, the enactment *24of OEC 601 effectively removed any authority of the trial court to employ common-law disqualifications, so long as the requirements of the rule are met. Laird C. Kirkpatrick, Oregon Evidence § 601.02, Art VI-2 (4th ed 2002).
Alternatively, the trial court ruled that “there is [a] substantial likelihood that the children’s testimony would not be helpful” to defendant. I can find nothing in the record that would permit the trial court to reach that conclusion. The trial court’s conclusion appears, again, to be based on pure speculation. Moreover, I am unaware of any cognizable rule of law that permits a trial court to exclude the testimony of lay witnesses on the ground that their testimony is not “helpful” to a particular party.4 In fact, OEC 402 provides that “ [a]ll relevant evidence is admissible, except as otherwise provided by the Oregon Evidence Code, by the Constitutions of the United States and Oregon or by Oregon statutory and decisional law.” In sum, the trial court’s expressed grounds for prohibiting defendant from subpoenaing his sons find no support in the rules of law that define the exercise of its discretion in this matter. Its ruling was legal error.
Although the trial court ultimately justified its refusal to permit defendant to subpoena his sons as witnesses on substantive grounds, the majority decides this matter on procedural grounds regarding appellate review. It acknowledges that defendant “repeatedly complained to the trial court that he wanted his children to testify.” 192 Or App at 16 n 1. Although reluctant to concede that defendant’s requests preserved the issue, the majority assumes for purposes of discussion that his statements to the court were sufficient to put the court on notice of his desire to have the opportunity to issue subpoenas. Nonetheless, the majority concludes that the issue is not reviewable because of an absence of proof. Alternatively, the majority asserts that, under State v. Bartel-Dawson, 176 Or App 519, 31 P3d 1129 (2001), we cannot determine whether the trial court’s error was harmless in the absence of a record regarding the nature *25of the children’s testimony. Because, according to the majority, defendant did not follow the correct procedure at the hearing, the issue he raises on appeal is not reviewable. It is correct that there are procedural irregularities in this case, but they fall at the feet of the trial court, which is charged by the constitution to afford due process to the parties that appear before it.
The record in this case begins with the trial court advising defendant of his statutory rights pursuant to ORS 426.100(1). The trial court was operating under difficult circumstances because defendant continued to interrupt the court, but nevertheless the court, with admirable patience, proceeded as the statute required. First, the court told defendant that he would be represented in the hearing by defense counsel, and it announced that “[defense counsel] will be appointed to represent [defendant] at this time[.]” Before the formal appointment by the court, defendant remarked, “Is he going to represent me? We had a little talk[.]” Next, the court explained what role defense counsel would play as defendant’s lawyer in the proceeding. Then, he told defendant about the power of subpoena, as quoted above. Defendant took the court at its word, but the court summarily ruled that “your sons are not going to be brought into your presence.” Despite continued pleas from defendant and his counsel, the court never wavered from that ruling.
It is within the above factual context that the analysis of the reviewability of defendant’s assignment of error begins. ORAP 5.45 requires preservation of an issue in a trial court in order to raise it on appeal. The purpose of the requirement is to give both parties the opportunity to present their positions and make their record in the trial court, thus providing the trial court an opportunity to understand and avoid or correct an error of law and the necessity of an appeal. State v. Brown, 310 Or 347, 356, 800 P2d 259 (1990). Here, the court ruled sua sponte. Consequently, no question arises as to whether the state had the opportunity to present its position to the trial court. Moreover, as will be discussed in more detail below, any motion to quash would have been premature. Also, because the court ruled sua sponte, the second purpose underlying the rule, that of permitting the court to avoid or correct any error, is also not at stake. It is clear then *26that the purposes underlying ORAP 5.45 were satisfied in this case by the record made by defendant in the trial court; if not by his own requests to the court to reconsider its ruling, then by defense counsel’s objection. Although counsel did not mention the Due Process Clause specifically when he told the trial court that he objected to its ruling under the United States Constitution, there can be no doubt that the trial court was aware of the issue; after all, it was the trial court that first told defendant about his right to subpoena witnesses.
The majority remains unsatisfied by the above record. Apparently, under the majority’s reasoning, defendant should have subpoenaed the witnesses in defiance of the trial court’s ruling. How or when defendant would have been able to issue subpoenas under the circumstances of this case after being advised by the trial court that it would not permit his children to testify, or why such an effort would not have been futile in light of the court’s ruling is not apparent from the record. Even after defendant’s counsel requested that the court permit the witnesses to be contacted by telephone and to testify in that fashion, the trial court ruled that “[t]he Court is satisfied * * * that there is substantial likelihood that the children’s evidence would not be helpful to [defendant] under these circumstances.” In other words, the court viewed its ultimate ruling as being based on the substantive weight of the children’s testimony and not on the failure of defendant to exercise the procedural predicate of the issuance of subpoenas.
The majority also hints that defendant was at fault in not asking for a continuance at some point during the hearing. However, defendant’s counsel was appointed minutes before defendant was advised of the right to subpoena witnesses. When advised of the right to subpoena witnesses, defendant immediately invoked it, and the court immediately told him that it was not going to permit him to subpoena his children. The record is susceptible of only one inference: the trial court ruled that it would not permit defendant’s sons to testify, and it was not about to change its mind regarding that ruling.
Second, the majority’s requirement of an offer of proof under these circumstances is error.
*27“Normally, an offer of proof is required to preserve error when a trial court excludes testimony. The purpose of the rule is to assure that appellate courts are able to determine whether it was error to exclude the evidence and whether any error was likely to have affected the result of the case.”
State v. Affeld, 307 Or 125, 128, 764 P2d 220 (1988). In Affeld, after the trial court limited the scope of cross-examination of a witness, the defendant did not make an offer as to what the witness would have said in response to the questions posed. 307 Or at 127.
The rule regarding the need to make an offer of proof does not apply when the ruling sought is not a ruling regarding the admissibility of evidence. For instance, the Supreme Court refused to require an offer of proof in State v. Olmstead, 310 Or 455, 800 P2d 277 (1990), where the trial court struck a defense of guilty by insanity as a matter of law after the defendant gave notice of his intent to raise the defense. The defendant never made an offer of proof at trial concerning the nature of his alleged mental disease or defect. Id. at 458. After the defendant was convicted, he appealed and assigned the trial court’s ruling as error. The Supreme Court asked the parties to respond to the question of whether the defendant was required to make an offer of proof to preserve the error. Id. It subsequently ruled that no offer of proof was required under those circumstances. Id. at 461. The court observed that one purpose of an offer of proof is to assure that appellate courts are able to determine whether the ruling was erroneous. The court said, “[i]n this situation, an offer would give us no additional information that bears on the legal question of the availability of the defense.” Id. (emphasis in original). The court added that another purpose of an offer of proof is to assure that the parties have the opportunity to make their record so that the trial court can make an informed ruling and correct any error. On the facts before it, the court said, “there is nothing to suggest that an offer would have altered the court’s analysis.”5 Id
*28This court also has recognized that offers of proof are not always necessary for purposes of the reviewability of an issue on appeal. In Kahn v. Pony Express Courier Corp., 173 Or App 127, 130, 20 P3d 837 (2001), rev den, 332 Or 518, 32 P3d 898 (2001) the trial court denied the defendants’ motion to compel production of documents. On appeal, the defendants assigned error to that ruling. The plaintiff responded that the defendants had not preserved the issue for appeal because they had failed to make an offer of proof about what the production would have demonstrated, if it had occurred. Id. at 131. Even though we cautioned that a party seeking production needed to make some showing that the documents sought were in fact subject to discovery, we rejected the argument that, under Affeld, an offer of proof was required. Id. at 132. In contrast to the facts in Affeld, we said, “[h]ere, however, the trial court did not exclude evidence; rather the trial court denied defendants’ motion to compel production of documents.” Id.
The ruling made in this case is analogous to the rulings made in Olmstead and in Kahn. In both of those cases, as well as in this case, the rulings are not primarily evidentiary rulings about the exclusion of particular testimony; rather, the rulings are procedural in nature and not dependent on the particular substantive evidence that could flow therefrom had the rulings not been made. As the court pointed out in Olmstead, “[w]hether an offer of proof was required depends on how we view the nature of the state’s motion and the trial court’s ruling.” 310 Or at 459. Defendant’s right to subpoena witnesses is an absolute legal right that requires no factual or evidentiary support. No offer of proof about what the sons would have said, if they had been called to testify, would have altered the right to subpoena them. It is those circumstances that make this case analogous to Olmstead, where the trial court struck a defense for lack of legal sufficiency as a matter of law without regard to any evidentiary record. Similarly, the trial court in Kahn was not asked to exclude particular testimony or evidence. Rather, as in this case, the trial court *29in that case ruled on a motion that was procedural in nature and constituted a predicate to the offer of particular evidence. For the reasons expressed in Olmstead and Kahn, the majority in this case errs by grafting the requirement of an offer of proof into ORAP 5.45 where the purposes of the rule are otherwise satisfied.
The majority is correct in one respect. The ordinary sequence of events that should have occurred, once defendant was apprised of his right to subpoena witnesses and invoked that right, would have been to permit the opportunity to exercise that right. But the court itself preempted the appropriate procedure by ruling sua sponte that “your sons are not going to be brought into your presence.” Any further motion to continue the hearing in order to subpoena witnesses to make an offer of proof would have been futile in light of the court’s preemptive ruling. As the court held in Olmstead, when a trial court “excludes an entire class of evidence by declaring, in advance, that it is inadmissible as a matter of law, the ruling renders a further offer futile.” 310 Or at 461.
Third, the majority contends that, “in the absence of a record as to the nature of the testimony that was thereby excluded, we cannot determine in this case whether the trial court’s supposed error in fact was harmless.” 192 Or App at 19. In support of that proposition, the majority cites to Bartel-Dawson. But in that case, the only issue was whether the trial court’s failure to advise the appellant in an involuntary commitment proceeding of her right to subpoena witnesses required reversal. Bartel-Dawson, 176 Or App at 520. We observed that the appellant was served before the hearing with a citation that informed her of the right to subpoena witnesses and that she, in fact, called a witness to testify on her behalf. Id. In light of those circumstances, we held that any error in the failure to advise her at the hearing of her right to subpoena witnesses was harmless error. Id.
The majority cites Bartel-Dawson for a proposition that is different from its holding. The majority says that the case is “[d]irectly on point” for the proposition that a “harmless error analysis still is required” even if the trial court deprived defendant of the ability to subpoena witnesses. 192 Or App at 18. But in substance, the majority’s point is the *30same as its conclusion that defendant was required to make an offer of proof about the content of defendant’s sons’ testimony. A “harmless error” requirement for purposes of appellate review functions for the same purposes as the requirement for an offer of proof regarding evidentiary matters. A judgment will not be reversed on appeal unless the appellant can demonstrate that the court’s ruling was prejudicial to the appellant’s case. Apparently, the majority means to say by its “harmless error” requirement that, in the absence of a record of the sons’ testimony in this case, we cannot discern whether we would have reached a different conclusion on de novo review than that of the trial court because of the strength of the evidence against defendant.
With respect, that assertion, in my view, begs the question when properly framed. The statutory right to be advised of the right to subpoena witnesses and the corresponding right to subpoena witnesses exist so that defendants in involuntary commitment proceedings, who are at risk of loss of their liberty, are provided with a hearing that supplies due process of law. A denial of the right to subpoena witnesses who have relevant testimony to offer about the statutory grounds for involuntary commitment so pervasively infects the nature of an involuntary mental commitment hearing that under no circumstances can a fair hearing be held without the exercise of the right. Consequently, the prejudice to defendant in this case is manifest, even without a showing of the specific testimony of the witnesses he wanted to call.
There is a certain irony regarding the majority’s reasoning and its result. In an emotionally charged setting with the liberty of defendant at stake, and in the midst of a hearing full of confusing outbursts in which the trial court was dealing, as best as it could, with constant interruptions by defendant, as well as others, defendant clearly invoked his right to subpoena identified witnesses. In just as clear of a manner, the trial court denied defendant’s invocation after indicating that it understood defendant’s and his counsel’s requests.6 We also know on this record, according to defendant’s statements to the court, that his sons could give relevant testimony regarding the issues before the court because *31they were the only potential witnesses who lived with him. Generally, appellate court doctrines of preservation of issues in trial courts, offers of proof, and “harmless error” analyses function so as to give appellate courts the necessary information to determine whether the trial court erred. The irony of the majority’s position is that we have in the record all the information that we need in order to conclude that the trial court erred when it denied defendant his right to subpoena witnesses.
Accordingly, I dissent.
Wollheim, J., joins in this dissent.The trial court found by clear and convincing evidence that defendant was dangerous to himself and unable to care for his personal, basic needs.
Apparently, defendant was referring to the individuals who were pursuing the involuntary commitment.
At the time of hearing, defendant was 47 years old.
OEC 701 limits the opinion testimony of lay witnesses to opinions or inferences that are rationally based on the perception of the witness and are “[hjelpful to a clear understanding of testimony of the witness or the determination of a fact in issue.” That rule does not prohibit a lay witness from testifying to relevant facts that the witness perceives.
The majority asserts that the holding in Olmstead is distinguishable from this case because, in that case, the trial court excluded an entire class of evidence as inadmissible as a matter of law whereas here the trial court excluded the testimony of defendant’s children because of its substantive content. The majority’s distinction is a distinction without a difference. Because an offer of proof would have *28been futile in light of the trial court’s ruling, it could make no difference regarding the reviewability of the issue on appeal, particularly in light of the fact that the majority does not undertake to affirm on the basis of the trial court’s substantive ruling.
The court told defendant regarding his request to subpoena his sons, “[l]etme be straight with you about that[.]”