Defendant-appellant David Haynes entered into a plea agreement on a cocaine possession charge on February 20, 2004, which included a waiver of the right to appeal any sentence of 108 months' imprisonment or less. On December 15, 2004, Haynes was sentenced to 70 months' imprisonment under the United States Sentencing Guidelines ("Guidelines"), despite defense counsel's objection to the constitutionality of the Guidelines in light of the Supreme Court's June 24, 2004, decision in Blakely v. Washington, 542 U.S. 296, 124 S. Ct. 2531, 159 L. Ed. 2d 403 (2004). On appeal, Haynes moves for a remand, relying on United States v. Booker, ___ U.S. ___, 125 S. Ct. 738, 160 L. Ed. 2d 621 (2005).1 The government, meanwhile, moves for dismissal of the appeal based on the appeal waiver contained in Haynes' plea agreement. Haynes argues that our recent case, United States v. Morgan, 406 F.3d 135 (2d Cir.2005) (on reconsideration of United States v. Morgan, 386 F.3d 376 (2d Cir.2004)), is distinguishable because of his explicit preservation at sentencing of the issue of the constitutionality of the Guidelines. We disagree, and hold that the appeal waiver at issue is enforceable against Haynes. We therefore deny Haynes's motion for remand and grant the government's motion to dismiss the appeal.

In Morgan, we considered whether a clause waiving any appeal of a sentence, in a plea agreement entered into prior to Booker, barred a subsequent appeal based on the district court's imposition of a sentence under the mandatory Guidelines regime. Morgan, 406 F.3d at 136. We held that the waiver was enforceable, citing two reasons. First, each party benefitted from the plea agreement: the defendant by limiting his criminal exposure and the government by a guaranteed outcome without the need for trial or appeal. Id. at 137. Second, appeal waivers are applicable to issues arising subsequent to the plea agreement, including issues created by new judicial decisions. Id. (citing Garcia-Santos v. United States, 273 F.3d 506, 509 (2d Cir.2001) and Brady v. United States, 397 U.S. 742, 757, 90 S. Ct. 1463, 25 L. Ed. 2d 747 (1970)). We noted that the possibility of changes in the law is simply one of the risks allocated by the parties' agreement. Morgan, 406 F.3d at 137.

There is no reason to disturb this logic in the present case. Haynes argues primarily that the preservation of the Guidelines issue at sentencing makes Morgan distinguishable. However, the effect of preservation is simply that our standard of review is one of harmless error rather than plain error. Fed.R.Crim.P. 52. This is certainly not an immaterial change, but it is irrelevant here, where the question is whether we even reach the issue of error. We observe, following the Morgan rationale, that the plea agreement conferred the benefits of certainty and limitation of criminal exposure2 on Haynes, and that the unconditional waiver of appeal for sentences of 108 months or less allocates the risk of subsequent changes in the law to Haynes. The fact that error was preserved at a sentencing subsequent to this receipt of benefits and allocation of risk does not affect either the receipt or the allocation.

We reiterate that a defendant may of course seek relief from the underlying plea where the plea was not knowing and voluntary, United States v. Ready, 82 F.3d 551, 557 (2d Cir.1996), or where sentencing was based on a constitutionally impermissible factor such as bias. United States v. Gomez-Perez, 215 F.3d 315, 319 (2d Cir.2000). Haynes has not sought this relief here.3 Nor could he succeed in such a claim. The plea allocution shows Haynes to have been fully informed, competent, free of coercion, and cognizant of his rights at the time of the plea. While ignorance of then-existing rights can invalidate a plea agreement in some cases, ignorance of future rights is unavoidable and not a basis for avoiding a plea agreement. Morgan, 406 F.3d at 137 n. 2. Finally, while it is apparent that a constitutional error was committed, it was not an error of reliance on a constitutionally impermissible factor within the meaning of Gomez-Perez. Morgan, 406 F.3d at 137 n. 3.

For the foregoing reasons, we hold that the Haynes's appeal waiver is enforceable despite his preservation of the Booker error at sentencing. Because Haynes does not and cannot challenge the validity of the underlying plea, his plea agreement bars the present appeal. We therefore deny Haynes's motion to remand for resentencing, and grant the government's motion to dismiss the appeal.