José Figuereo pled guilty to being found in the United States after having been deported, a violation of 8 U.S.C. § 1326 (2003). In calculating Figuereo's sentence of 57 months' imprisonment and three years of supervised release, the district court added two criminal history points pursuant to United States Sentencing Guideline ("U.S.S.G.") § 4A1.1(d) (2003) because Figuereo committed the instant offense — being found in the United States — while serving a state prison sentence. Figuereo appeals his sentence, arguing that the district court erred in applying § 4A1.1(d) and in treating the Guidelines as mandatory. He also challenges the drug testing and treatment condition of his supervised release, arguing that the court improperly delegated its authority to a probation officer. We remand for the limited purpose of adjusting the drug treatment and testing condition but affirm the rest of the sentence.

The facts in this case are undisputed. Figuereo, a Dominican national, was deported from the United States in 1992 following his conviction for various drug-related misdemeanors and felonies. He re-entered the country without permission in 1999.

In May 2002, Figuereo was arrested in Puerto Rico on drug charges. He was subsequently convicted in Puerto Rico Superior Court and sentenced to one year in prison. While Figuereo was serving his sentence, he participated in a routine interview with the Alien Criminal Apprehension Program for the Department of Homeland Security. In that interview, Figuereo claimed to be David Figueroa-Figuereo, a legal permanent resident of the United States. Further investigation revealed Figuereo's true identity and the fact of his previous conviction and deportation.

On April 30, 2003, a federal grand jury indicted Figuereo on one count of entering the United States as an alien previously deported following a conviction for an aggravated felony, 8 U.S.C. § 1326(b)(2).1 Figuereo pled guilty to this count on July 14, 2003. On November 10, 2003, the district court sentenced Figuereo under the then mandatory Guidelines to 57 months in prison, the bottom of the applicable sentencing range, and three years of supervised release. That sentence reflects a two-point increase in Figuereo's criminal history under U.S.S.G. § 4A1.1(d), which mandates such an increase "if the defendant committed the instant offense while under any criminal justice sentence." The court also imposed numerous conditions of supervised release, one of which provided that:

The defendant shall ... submit to a drug test within fifteen (15) days of release ... and at least two (2) tests thereafter when so requested by the U.S. Probation Officer. If any such samples detect substance abuse, the defendant shall, at the discretion of the U.S. Probation Officer, participate in a substance abuse treatment program, arranged and approved by the U.S. Probation Officer.

Figuereo filed a timely appeal, challenging his sentence and the condition of supervised release relating to drug testing and treatment.

Section 4A1.1(d) of the Sentencing Guidelines instructs a court calculating a defendant's criminal history level to "[a]dd 2 points if the defendant committed the instant offense while under any criminal justice sentence, including ... imprisonment." Here, Figuereo's offense was being "found in[ ] the United States" in violation of 8 U.S.C. § 1326. Because he was serving a state prison sentence when the Department of Homeland Security "found" him, the district court concluded that § 4A1.1(d) applied and added two criminal history points. Figuereo now asserts for the first time on appeal that § 4A1.1(d) cannot apply without a mens rea component.2

We typically review the district court's factual findings for clear error and its interpretation and application of the sentencing guidelines de novo. United States v. Savarese, 385 F.3d 15, 18 (1st Cir.2004). Where the defendant raises objections on appeal that were not presented to the district court, however, the standard is different.3 Under these circumstances, "our review is restricted to plain error." United States v. Carrasco-Mateo, 389 F.3d 239, 243 (1st Cir.2004). Plain error is a deferential standard under which errors will be corrected only if the defendant shows "(1) that an error occurred (2) which was clear or obvious and which not only (3) affected the defendant's substantial rights, but also (4) seriously impaired the fairness, integrity, or public reputation of judicial proceedings." United States v. Duarte, 246 F.3d 56, 60 (1st Cir.2001).

Emphasizing Supreme Court precedent disfavoring offenses that lack a mens rea requirement, see Staples v. United States, 511 U.S. 600, 606, 114 S. Ct. 1793, 128 L. Ed. 2d 608 (1994), Figuereo asserts that the court erred in applying the § 4A1.1(d) enhancement without regard to the voluntariness of his conduct. In other words, he contends that because he did not have the option of leaving the United States once he was imprisoned, his sentence for being "found" while in prison cannot be more severe than if he had been "found" before being imprisoned. We disagree.

Section 4A1.1(d) defines a sentencing enhancement, not an element of the offense. See Harris v. United States, 536 U.S. 545, 549, 122 S. Ct. 2406, 153 L. Ed. 2d 524 (2002) (distinguishing between elements of a crime and sentencing factors on the ground that the latter are "not subject to the Constitution's indictment, jury, and proof requirements"). Several of our sister circuits have concluded that Guidelines sentencing factors need not include a mens rea requirement. See, e.g., United States v. Gonzalez, 262 F.3d 867, 870 (9th Cir.2001); but see United States v. Schnell, 982 F.2d 216, 220-21 (7th Cir.1992) (rejecting a categorical rule that sentencing enhancements do not require a mens rea element, but concluding that the particular enhancement at issue did not violate due process despite absence of such an element). Moreover, at least two of our sister circuits have upheld § 4A1.1(d) enhancements for defendants who were "found" in the United States in violation of 8 U.S.C. § 1326 while they were imprisoned. See United States v. Coeur, 196 F.3d 1344, 1346 (11th Cir.1999); United States v. Santana-Castellano, 74 F.3d 593, 598 (5th Cir.1996).

The fact of being under a criminal justice sentence is a sentencing factor for violations of 8 U.S.C. § 1326, not an element of the crime of being "found" in the United States.4 It was thus not plain error for the district court to follow our sister circuits in applying the § 4A1.1(d) enhancement to a defendant who was "found" in the United States while imprisoned.5

Figuereo also argues for the first time on appeal that he is entitled to resentencing in light of the Supreme Court's recent decision in United States v. Booker, ___ U.S. ___, ___-___, 125 S. Ct. 738, 764-75, 160 L. Ed. 2d 621 (2005) (Breyer, J.), which rendered the Guidelines advisory rather than mandatory. To prevail on an unpreserved Booker claim, a defendant must show not only that he was sentenced under the mandatory Guidelines, but also that there are "circumstances creating a reasonable probability that the district court would impose a different sentence more favorable to the defendant under the new `advisory Guidelines' Booker regime." United States v. Antonakopoulos, 399 F.3d 68, 75 (1st Cir.2005); see also United States v. Heldeman, 402 F.3d 220, 222 (1st Cir.2005) (describing the Booker plain error inquiry as whether "there is reasonable indication that the district judge might well have reached a different result under advisory guidelines").

At sentencing, Figuereo asked the district court to "be considerate" to him, explaining that, "I came here on account of my children, because as you know, I have my children [in the United States], and I was just coming here to try to see them, and all the crimes that I have committed have been the result of my drug abuse." Emphasizing that mandatory Guidelines precluded the sentencing court from taking such mitigating factors into account, see Antonakopoulos, 399 F.3d at 81, Figuereo asserts that he should be resentenced under the advisory regime to allow the court to reconsider his request.

There is no indication, however, that the court would have imposed a more lenient sentence in light of Figuereo's request even if it had been free to do so, particularly given what it described as Figuereo's "extensive" criminal history.6 The court did not comment on Figuereo's family ties or history of drug abuse despite Figuereo's invocation of these factors at sentencing and references to them in the pre-sentence report ("PSR"). Cf. Heldeman, 402 F.3d 220, 222. Moreover, the PSR indicated that although Figuereo has four children in the United States, he does not have a relationship with any of them beyond providing child support for one daughter. Thus, the court might well have viewed his claim to have returned to the United States "on account of my children" with some skepticism.

"Even post-Booker, the district court `must consult [the] Guidelines and take them into account when sentencing.'" United States v. Serrano-Beauvaix, 400 F.3d 50, 55 (1st Cir.2005) (quoting Booker, 125 S.Ct. at 767). The Guidelines in this case dictated a sentencing range of 57 to 71 months in prison. Pursuant to the plea agreement, the district court sentenced Figuereo to the bottom of that range. Figuereo has failed to demonstrate a reasonable probability that, having consulted the Guidelines, the district court would impose a lower sentence on remand. His Booker claim therefore fails.

C. Drug testing and treatment release condition

Figuereo also contends for the first time on appeal that the district court impermissibly delegated authority to the probation officer to decide how many drug tests to administer and whether to order him to attend a drug treatment program if he failed a drug test while on supervised release. This delegation constitutes plain error under United States v. Meléndez-Santana, 353 F.3d 93 (1st Cir.2003), in which we held that a sentencing court "may not ... vest the probation officer with the discretion to order an unlimited number of drug tests" and must determine whether the defendant has to undergo drug treatment "either at the time of sentencing, or later in response to a motion by the probation officer." Id. at 101-03 (footnote omitted). The government concedes plain error and agrees that this court should remand for limited resentencing on this basis. We therefore remand for an adjustment of the drug testing and treatment portion of the sentence.7 See United States v. Vega, 398 F.3d 149, 154 (1st Cir.2005) (vacating the defendant's sentence "only to the extent it delegates the terms of his drug testing and treatment during the period of his supervised release, and remand [ing] for resentencing on this sole issue"). The remainder of Figuereo's sentence is affirmed.

So ordered.