dissenting.
I respectfully dissent from the majority’s conclusion that the reasonable notice required by Burns v. United States, 501 U.S. 129, 111 S.Ct. 2182, 115 L.Ed.2d 123 (1991), and Federal Rule of Criminal Procedure 32(h) is inapplicable to Guidelines variances. The majority’s rejection of a reasonable notice requirement in favor of a new standard based on whether “some ground or factor ... would unfairly surprise competent and reasonably prepared counsel” leaves district court judges without the very guidance the majority purports to offer them. Indeed, the government now also agrees that the reasonable notice required by Burns and Rule 32(h) must apply to Guidelines variances to ensure full adversarial testing of the issues related to sentencing.
Moreover, having further considered the issue in the context of en banc briefing and argument, I have become convinced that the reasonable notice requirement means notice of a possible variance being contemplated by the judge in advance of the sentencing hearing. Such prehearing notice is most consistent with Rule 32’s directive that parties be given the opportunity to comment on matters “relating to an appropriate sentence.” Fed.R.Crim.P. 32(i)(1)(C). This rule does not mean that every failure to give prehearing notice will require a new proceeding. Such errors lend themselves to harmless error review. In this case, however, I cannot find that the error was harmless, and I therefore would vacate Vega’s sentence and remand for a new sentencing hearing.
I.
My conclusion that notice may be deemed “reasonable” only if given in advance of the sentencing hearing is informed by multiple considerations. Most importantly, the interest at stake for the defendant — the length of incarceration— could not be more critical, even when the potential difference in a defendant’s sentence would be “merely” a matter of months. Whether or not the Due Process Clause is implicated,7 the defendant’s op*9portunity to comment meaningfully when a court contemplates a sentence outside the Guidelines is of utmost importance.
It also is significant, as the panel opinion observed, that implicit in Bums and Rule 32(h) “is the understanding that Rule 32(h) notice would serve as an alternative to the forms of prehearing notice expressly referenced” in the rule, i.e., the presentence report or a party’s prehearing submission. United States v. Vega-Santiago, 519 F.3d 14, 2007 WL 3171337, at *12 (1st Cir. Oct. 31, 2007) (emphasis in original). Thus, a rule of pre-hearing notice is more consistent with the principles articulated in Bums and incorporated into Rule 32.8 To require counsel to respond off-the-cuff to a previously unannounced rationale for a non-Guidelines sentence is to deny the very period of deliberation that “notice” is intended to guarantee. Even when competent counsel is familiar with all of the facts of the crime and the general principles of sentencing law, he or she may not immediately appreciate their relevance to the proposed variance from the Guidelines. Accord United States v. Calzada-Maravillas, 443 F.3d 1301, 1304 (10th Cir.2006) (observing that the “key component” of' the notice requirement is “notice in advance of the sentencing hearing”).
In addition, a bright-line rule of prehearing notice would provide unambiguous direction to both the parties and the court, with minimal burden. We must keep in perspective the small number of cases at issue here. At the en banc oral argument, the government represented that, in most instances, departures or variances are either proposed by the Probation Department in the presentence report or requested by one of the parties. This understanding that sua sponte variances by the court occur infrequently informed the conclusion reached by the original panel, which included an experienced district court judge. It will be the exceptional occasion when a court must provide its own prehearing notice of a contemplated ground for a variance; in such instances, the court would be able to alert the parties with a brief written order. A continuance would be necessary even more rarely, when a rationale for a variance first arises at the sentencing hearing.
Moreover, requiring that notice be given as a matter of course before the hearing reduces the possibility that the court will be blind-sided by a party’s last-minute attempt to secure a non-Guidelines sentence. The judge is obviously in a better position to evaluate the merits of a variance if it is proposed in advance. With a rule of advance notice, the government and defendant .will have greater incentive to present all arguments for a non-Guidelines sentence in their prehearing submissions, facilitating sentencing proceedings that most fairly take into account all relevant considerations.
However, even a rule of advance notice will not eliminate some questions of reasonableness. The content of the notice and its timing in relation to the date of the hearing and the issues to be addressed are elements of reasonableness. As for content, the panel opinion pointed to the requirement in Bums that the notice “specifically identify the ground on which the district court is contemplating an upward departure.” 501 U.S. at 138-39, 111 S.Ct. 2182. A similar requirement should apply *10to a contemplated variance. Any less exacting requirement would impose on the parties “the burden of guessing the particular grounds on which the court might choose to increase [or decrease] the sentence.” Vega-Santiago, 519 F.3d at 29, 2007 WL 3171337, at *11.
As for timing, reasonableness will depend on whether the parties were given sufficient opportunity to prepare meaningful comment on the previously unannounced ground for deviating from the Guidelines. If addressing the court’s contemplated rationale would require minimal legal research or investigation of facts, a brief period of time would be adequate. But if, for example, the court announced that it might rely on mitigation evidence presented in letters submitted by multiple individuals, the parties might need time to review the submissions and conduct further investigation. In such circumstances, reasonable notice would have to be given far enough in advance of the hearing to accommodate such preparation.
Regardless of the complexity or novelty of the court’s sua sponte rationale, at least some advance warning is crucial to ensure the most effective advocacy and, in turn, “the thorough adversarial testing contemplated by federal sentencing procedure,” Rita v. United States, — U.S.-, 127 S.Ct. 2456, 2465, 168 L.Ed.2d 203 (2007). Other circuits also have explicitly adopted this view. See, e.g., United States v. Cole, 496 F.3d 188, 191 (2d Cir.2007) (“[N]otiee given during the course of the sentencing hearing and put into effect less than two hours later was insufficient.”); United States v. Flanders, 491 F.3d 1197, 1220 (10th Cir.2007) (finding that the court’s announcement on the first day of sentencing that it might impose a non-Guidelines sentence was “plainly insufficient under Rule 32(h)”).
A failure to provide reasonable notice will not always require resentencing. In some cases, the reviewing court may be satisfied that lack of proper notice was harmless because it would not have placed the defendant in a position to comment more effectively on the proposed variance. Where, for example, counsel had the opportunity to provide a thoughtful response to the court’s rationale for a variance and where the defendant on appeal offered no additional rebuttal to the court’s rationale, it would be appropriate to conclude that the lack of notice was harmless. If, however, a defendant identifies plausible rebuttals to the court’s rationale that could have been made if counsel had been given time to prepare, the principles of Bums require resentencing. Otherwise, “a critical sentencing determination will go untested by the adversarial process contemplated by Rule 32 and the Guidelines.” Burns, 501 U.S. at 137, 111 S.Ct. 2182.
The harmless error analysis addresses many of the same considerations that were included in the panel’s favorable evaluation of the reasonableness of the notice provided near the outset of the sentencing hearing in this case. However, for the reasons stated, I now conclude that the better approach is to make advance notice the rule and to engage in harmless error review when the rule is violated. As I explain in the following section, the error in this case was not harmless.
II.
As soon as the government proposed at Vega’s sentencing hearing that the court go beyond the Guidelines term of 57 to 71 months, his counsel protested that the defense should have been advised in advance “so it can be prepared to rebut these arguments.” The court disagreed that notice was required, heard testimony from the victims, and explained that the crime war*11ranted a higher sentence because, inter alia, it involved a home invasion with a shooting and was therefore “not a regular car jacking.” Counsel unsuccessfully argued in response that the presentence report and the Guidelines recommendation took the particular facts of the crime into account. In announcing the sentence, the court referred to defendant’s “invad[ing] the privacy of a home in the middle of the night,” the victim’s plea for mercy, and the discharge of the weapon.
In his en banc brief, Vega offers several arguments that could have been made at the sentencing hearing if counsel had received advance notice that the court was contemplating a variance based on the specific details of the offense:9
• In response to the court’s concern that the carjacking was unusual because it involved a home invasion that caused serious psychological injury to the victims, counsel could [have] challenged the veracity of the victims’ claims of paralyzing fear, noting that [the victim] responded to the robbery by getting a gun, firing 13 shots at Mr. Vega-Santiago as he drove away on a public street, and then reloading and “go[ing] after the defendant” with his friend in an SUV. Counsel also could have argued that being robbed and fired upon by an armed gunman in any location causes serious emotional trauma, and that the marginal cost of enduring the crime at home, as opposed to numerous other private locations, does not justify a variance from the guideline range.
• In response to the court’s reliance on the shot fired during the robbery, counsel could have pointed out that the mandatory consecutive sentence on Count Two already reflected a three-year increase because “the firearm [was] discharged” rather than merely “brandished.” Compare 18 U.S.C. § 924(c)(1)(A)(iii) (ten-year mandatory minimum), with 18 U.S.C. § 924(c)(l)(A)(ii) (seven-year mandatory minimum).
• In response to the court’s reliance on the death threat and pleas for mercy, counsel could have explained the effect of the guideline adjustment for death threats, U.S.S.G. § 2B3.1(b)(2)(F), which was applied in this case, and could have reminded the court of “the need to avoid unwarranted sentence disparities among defendants with similar records who have been found guilty of similar conduct,” 18 U.S.C. § 3553(a)(6).
Appellant’s En Banc Brief at 21-22 (citations omitted).
These arguments, which directly challenge the need for a non-Guidelines sentence to meet the court’s objectives, are neither frivolous nor tangential to the court’s reasoning. We cannot know their impact on the court if counsel had the opportunity to present them at the sentencing hearing. The court expressed concern that Vega’s sentence “reflect how serious this offense was.” Although defense counsel argued at the hearing that the Guidelines sentencing range would accomplish that purpose, the brief adds specific content, supported by authority, to the more general argument that the Guidelines already accounted for the facts that bothered the judge. It is precisely this sort of developed presentation by counsel, reinforced by legal and factual references, that is denied a defendant who is not given advance notice of the court’s contemplated grounds for a non-Guidelines sentence. *12Moreover, in its explanation for the sentence, the court also referred to Vega’s admission that he had “previous brushes with the law which included violent crime allegations for which he was not convicted” — a basis for deviating that the court had not previously mentioned and for which, therefore, no notice was provided.
Where, as here, a defendant demonstrates that lack of notice deprived him of “full adversary testing of the issues relevant” to his sentence, Burns, 501 U.S. at 135, 111 S.Ct. 2182, the error cannot be deemed harmless and a remand for resentencing is necessary.
III.
The majority predicts that “a mechanical notice rule” would cause undesirable consequences. In their view, it would cause judges to “shy away from imposing non-guideline sentences that the parties had not proposed in advance,” or, alternatively, “the judge would often have to employ a burdensome two-stage regime.” Neither of these assertions has merit.
A. Multiple Proceedings
The majority’s concern that an advance notice rule would often require a two-stage sentencing process reveals a fundamental misunderstanding of the sentencing process. My colleagues appear to believe that a judge enters the courtroom for a sentencing hearing with little sense of the sentence he or she intends to impose or the factors that will affect that sentence. They assume that these factors will become apparent only during the course of the hearing and that, if notice is required for a decision to deviate from the Guidelines, many variances will require a continuance and second hearing.
That concern is at odds with reality. While the majority may be correct that a judge will not make a final sentencing decision until the end of the hearing, and “may well be revising his views depending on what is presented and how counsel respond to questions,” the judge will arrive at that hearing after a review of the presentence report and other relevant materials. He or she will already have a developed view of what the appropriate sentence is, including its length. To be sure, the judge’s views may be altered by what he or she hears at the hearing. But a judge will almost always have considered in advance of the hearing whether an upward or downward variance is appropriate. To suggest less forethought on the part of the sentencing judge is to suggest that the judge enters the hearing unprepared.
In other words, the ultimate decision to deviate from the Guidelines' — made at the conclusion of the sentencing hearing, after adversary testing of the issues — should not be confused with the earlier inclination— developed before the hearing — to focus attention on particular factors that might warrant such a deviation. The notice required by Rule 32(h) is not that a court will impose a variance, but only that it is considering factors that may justify a variance. Hence, it would pose no burden for the court to provide notice in advance of the hearing that such a variance is contemplated. In those few instances where the court’s inclination to impose a variance is based on a factor or factors raised for the first time at the hearing, the principles of Bums and Rule 32(h) require the court to provide sufficient notice to enable both the defendant and the government to consider, research and thoughtfully respond to the new ground. In that case a continuance of the sentencing hearing would be required. Such continuances would be a small price to pay for the fairness to all parties of the advance notice requirement.
B. The Role of the Guidelines
The notion that a rule of advance notice would inappropriately incline judges to*13ward the Guidelines is also seriously flawed. In multiple cases this term, the Supreme Court has explicitly confirmed that the Guidelines remain a central part of the sentencing process post-Booker. The Guidelines are “the starting point and the initial benchmark” for sentencing decisions, Gall v. United States, — U.S. -, 128 S.Ct. 586, 596, 169 L.Ed.2d 445 (2007), entitled to “respectful consideration,” Kimbrough v. United States, — U.S. -, 128 S.Ct. 558, 570, 169 L.Ed.2d 481 (2007), because “in the ordinary case, the [Sentencing] Commission’s recommendation of a sentencing range will ‘reflect a rough approximation of sentences that might achieve § 3553(a)’s objectives,’ ” id. at 574 (quoting Rita, 127 S.Ct. at 2465). See also United States v. Jiménez-Beltre, 440 F.3d 514, 518 (1st Cir.2006) (en banc) (holding that the district court normally should begin with a Guidelines calculation).
The majority does not dispute the continuing centrality of the Guidelines to the sentencing process. Indeed, they acknowledge the Guidelines’ “gravitational pull.” They worry, however, that an advance notice requirement will increase the Guidelines’ pull on district court judges and hence could compromise the changes in the sentencing process effected by the Supreme Court in Booker and its progeny. The suggestion that district court judges would shy away from sua sponte variances as a matter of convenience is misguided. It is inconceivable to me that, having given the Guidelines due consideration and finding them lacking, a judge would suppress the independent judgment required by the Supreme Court simply to avoid providing the parties with reasonable prehearing notice. The modest burden of preparing a brief notice or, in the rare case, continuing an already convened sentencing hearing to a later date would not deter a judge from imposing a variance.
Rather than justifying less notice, the broader sentencing discretion afforded to district judges post -Booker requires that defendants be given the same advance warning of the court’s contemplated rationale for deviating from the Guidelines that Bums required for sentencing departures. As the panel opinion observed, the need for notice remains acute because of the virtually limitless number of factors that may be used to support a variance. Although notice under Rule 32 is owed to both the defendant and the government, the defendant’s interest in preparing the most persuasive argument available against an upward variance is obviously of particular significance. Defendants should not be placed in the untenable position of “trying to anticipate and negate every conceivable ground on which the district court might choose to depart on its own initiative” or risk allowing “a critical sentencing determination [to] go untested by the adversarial process.” Burns, 501 U.S. at 137, 111 S.Ct. 2182.
The majority acknowledges that there are some cases where, as a matter of fairness, notice must be provided. But the majority’s proposed approach — providing notice or granting a continuance when the court proposes to rely on a ground that would “unfairly surprise competent and reasonably prepared counsel” — -has at least three serious flaws. First, it gives no guidance at all to district judges. Without an anchor in either the Due Process Clause or a bright-line rule, the majority’s standard offers sentencing judges no framework within which to evaluate the need for notice. Fairness, surprise and reasonable preparation are all elusive concepts that individual judges will see differently.
Second, the ambiguity of the standard leaves every non-Guidelines sentence that was imposed without notice open to chai*14lenge on appeal. Surprise arguably exists any time the court announces, for the first time at the sentencing hearing, its sua sponte intention to deviate from the Guidelines, and surprise will rarely be deemed “fair” by a defendant who has a right, under Rule 32, to comment on matters affecting the length of his incarceration. See Fed.R.Crim.P. 32(i)(1)(C). Debate over what it means for counsel to be “reasonably prepared” for a sentencing hearing surely will consume more judicial time than judges would expend in giving prehearing notice. Moreover, the standard is so vague that appellate courts could rarely, if ever, conclude that the sentencing court had erred.
Third, the majority suggests that most cases would not involve unfair surprise because courts typically would base variances on “[gjarden variety considerations” such as the likelihood of recidivism or the seriousness of the crime. But the commonality of such factors is not the issue. What matters is how the court is processing all of the information relevant to those factors and its inclination to take an exceptional view of them. In the absence of advance notice, neither the defendant nor the government has reason to anticipate that the usual factors may lead to a non-Guidelines sentence, and advocating for a lower sentence or higher sentence within a Guidelines range is not the same as advocating against the court’s inclination to sentence outside the Guidelines. That difference is reflected in the new arguments asserted in Vega’s en banc brief, which specifically emphasize why the court’s concerns did not require a sentence beyond the Guidelines.
In sum, an easily administered bright-line rule requiring advance notice in all cases would promote both actual fairness in sentencing and “the perception of fair sentencing,” Gall, 128 S.Ct. at 597, without undue burdens on the courts. The Supreme Court already has recognized the need for a reasonable notice requirement in the context of departures. In the post-Booker era, when the court has broader discretion to go outside the Guidelines, notice remains a critical component of the defendant’s right to meaningfully comment on the appropriateness of a non-Guidelines sentence. I therefore respectfully dissent.
. The Supreme Court noted in Bums that its construction of Rule 32 avoided "the serious question whether notice in this setting is man*9dated by the Due Process Clause.” 501 U.S. at 138, 111 S.Ct. 2182.
. I am, of course, well aware that Rule 32(h) applies by its terms only to sentencing departures. It is the principles of Bums, which are reflected in Rule 32(h), that make the notice requirement equally applicable to sentencing variances.
. Although these arguments were not made to the panel, I deem it appropriate to consider them on en banc review because we specifically invited argument on the notice issue.