PATRICK E. HIGGINBOTHAM, Circuit Judge:

In this case, we must decide whether the district court's imposition of a condition of supervised release prohibiting the defendant from "residing or going to places where a minor or minors are known to frequent without prior approval of the probation officer" was plainly erroneous. We conclude it was not and AFFIRM.

I.

In January 1990, Michael Fields was convicted in Wisconsin state court of second degree sexual assault of a child.1 He was sentenced to five years in prison, but only served one year; the rest of his term was probated. Fields was required to register as a sex offender in Wisconsin for the rest of his life. Because of this conviction, he must also register as a sex offender in Texas. Fields has thrice been arrested and convicted for failing to register as a sex offender.2 He has also been repeatedly told by state authorities in both Wisconsin and Texas that he must register as a sex offender, instructions with which it appears he has never complied.3

Fields was arrested by the Austin Police Department for failing to register as a sex offender in April 2013. The next month, he was indicted in federal court and charged with one count of failing to register as a sex offender in violation of the Sex Offender Registration and Notification Act ("SORNA").4 After unsuccessfully moving to dismiss the indictment on the grounds that SORNA was unconstitutional, Fields pled guilty in July 2013.

In November 2013, Fields appeared before the district court for his sentencing hearing. At that hearing, the court reviewed Fields's criminal history record, and concluded that, even discounting several convictions where it was disputed as to whether Fields committed the crime, he had "a solid criminal record since 1974." After hearing from counsel, the court then sentenced Fields to a 27-month sentence of imprisonment, followed by ten years of supervised release. The supervision included a number of conditions, including, as relevant here, a requirement that:

Fields did not object to this condition. This timely appeal follows.

II.

We normally review conditions of supervised release for abuse of discretion.5 In this case, because Fields did not object to his supervised release condition while before the district court, we review for plain error.6 As the Supreme Court has made clear, plain error is a demanding standard:

In considering whether an error is "clear or obvious" we look to the "state of the law at the time of appeal,"8 and we must decide whether controlling circuit or Supreme Court precedent has reached the issue in question, or whether the legal question would be subject to "reasonable dispute."9

a.

In imposing special conditions of supervised release, the district court has "extensive," but not unbridled, discretion.10 That discretion is bound in two ways. First, the condition must be "reasonably related" to one of four statutory factors:

Second, "the condition cannot impose any greater deprivation of liberty than is reasonably necessary" to accomplish the purposes set out in 18 U.S.C. § 3553(a).12 Fields challenges his special condition on both grounds.

Set against these permissive standards, it is not obvious to us that the district court's decision to impose a condition restricting Fields's ability to "resid[e] or go[] to places where a minor or minors are known to frequent without prior approval of the probation officer" was error. And even if there were error, we could not hold that the error was plain.

1.

The first statutory condition is "the nature and characteristics of the offense and the history and characteristics of the defendant."13 Two points of history are relevant: Fields's underlying sexual assault conviction in 1990 and his repeated convictions for failing to register as a sex offender.

Turning first to the original sexual assault conviction, we have held that "[b]ecause district courts must consider the defendant's history and characteristics, they may take into account `a defendant's prior conviction for a sex offense when imposing sex-offender-related special conditions when the underlying conviction is for a non-sexual offense.'"14 Our court, along with our sister circuits, has under such circumstances repeatedly affirmed special conditions that require sex offender treatment or, as here, limit where the defendant may go. We have done so even when, as here, the underlying sexual offense occurred many years before, and the conviction leading to the imposition of the special condition was non-sexual in nature.15 In doing so, we do not require a perfect fit between past offense and current condition. Even so, the government must demonstrate some connection between criminal history and special condition. For example, in United States v. Salazar,16 the district court imposed a special condition prohibiting the defendant from "purchasing, possessing, or using any sexually stimulating or sexually orienting materials," after he was convicted of failing to register as a sex offender.17 We held that this special condition was not reasonably related to the circumstances of the offense or the history and characteristics of the defendant because there was no evidence of "predatory sexual behavior beyond his singular and now-remote sexual offense" or that "sexually stimulating materials fueled his past crimes."18

Fields's criminal history, as with that of the defendant in Salazar, involves a single, remote sexual offense. His prior conviction for sexual assault of a child, however, does bear some relationship to the special condition limiting access to places frequented by children — unlike Salazar, where there was no evidence that pornography had anything to do with the underlying sex crime, here, access to children was a necessary predicate to Fields's original sexual assault offense.

Moreover, in evaluating the defendant's history, we have held that the defendant's "refusal to register, despite multiple warnings from [state] officials, culminating in his guilty plea to the crime [of refusal to register], evidences a refusal to abide by the restrictions placed on sex offenders thereby undermining efforts to combat sex-offender recidivism."19 Pursuant to this holding, were we unable to sustain Fields's condition under the first statutory consideration, we could do so under the second or third provision. Specifically, Fields's restrictions can be justified either because his history of noncompliance with punitive restrictions requires a harsher response, the second statutory consideration, or because the defendant, who has shown an unwillingness to comply with a provision designed to protect the general populace, poses a greater risk to the public, the third statutory consideration.20 Putting these two factors together — a history of sexual assault of children along with a failure to respond to the "first order" remedy of registration — the district court could reasonably have concluded that stronger remedial measures were necessary.

Even were we to find otherwise, and hold that the district court was in error, we cannot conclude such error would be "clear or obvious."21 Courts within our circuit have affirmed similar (or identical) conditions in similar contexts.22 Nor has Fields been able to identify an on-point circuit case clearly demonstrating that the district court's condition was not reasonably related to the statutory factors — and we have held that if the law is unsettled within the circuit, any error cannot be plain.23

2.

The second issue is whether the condition is a greater deprivation of Fields's liberty than reasonably necessary to accomplish the goals of the statutory scheme. We begin our analysis with United States v. Windless.24 There, our court faced a similar question. The defendant had been convicted nearly two decades before the appeal of sexually assaulting a child and was required to register as a sexual offender.25 He had been repeatedly charged with failing to register as a predatory offender, though he was never found guilty of any additional sexual assaults, and was convicted in federal court of failing to register as a sex offender.26 The district court imposed a special condition requiring that "[t]he defendant shall have no direct or indirect contact with any children under the age of 18, unless accompanied and supervised by an adult, who has been approved in advance by the probation officer."27

Reviewing for abuse of discretion, we reversed. We concluded that "to forbid all `indirect' contact [with children] works a serious restriction on liberty, making a trip to the grocery store or a place of worship a trip that may end in imprisonment via revocation sentence."28 While a defendant's conduct might warrant such a condition under certain circumstances, we held that:

In short, a condition that would severely limit where a defendant could go in public, based mainly on a history of violating registration requirements, was unwarranted.30

The appropriateness of the supervised release condition is a function of the severity of the offense history and the impact of the restriction. Fields and Windless have similar criminal histories, and of the four criteria highlighted by the Windless court, the first three are identical. Both were sentenced for failing to register as a sex offender, the event that precipitated the registration requirement is not recent, and there is no evidence of any subsequent crimes against children.31 The fourth factor, previous failures to register, cuts differently. The Windless court concluded that Windless had "failed to register only twice before."32 While Fields was only convicted two other times of failing to register, the PSR reports at least two other instances where he was told by Texas or Wisconsin state authorities that he needed to register and where he failed to do so, a conclusion he does not challenge. Even still, the criminal histories are close enough that if Fields's condition has a similar impact to that which the court perceived in Windless, under our precedent it ought fall.

We conclude that Fields's restriction is not comparably severe. The condition at issue prohibits Fields from "going to places where a minor or minors are known to frequent without prior approval of the probation officer." The word "frequent" serves as an important modifier — it limits the zone of forbidden locations to those that children "visit often" or "associate with, be in, or resort to often or habitually."33 By our read, this would include places like schools and playgrounds, but would not include locations such as grocery stores, places of worship, transportation hubs, and most stores. Children, to be sure, can and do attend such places — but they do not "frequent" them. In this respect, the restraint on Fields's liberty, while by no means trivial, is not as extensive as the restraint in Windless.

Furthermore, Fields has the benefit of ex ante knowledge about which places are safe for him to go, as "places where minors are known to frequent" is an objective standard that can be determined in advance, especially through consultation with his probation officer. Finally, we note that Fields can seek permission from his probation officer to go to places that children frequent. "If such permission is unfairly denied, the district court can modify this term."34 We have recognized before, and reaffirm now, that a modifiable condition such as this one works a less significant deprivation of liberty than one which cannot be altered.35

In any event, even were we to find that the condition was error, that error was not clear or obvious. The defendant cannot point to any case law concluding that the imposition of the type of restriction at issue here was error. Our court has, however, thrice ruled in unpublished decisions that the condition at issue here was not plainly erroneous.36 While a decision ruling that an error is not plain does not necessarily mean that it was not clear or obvious, given the additional criteria which must be found before a court may find plain error, we have looked to rulings rejecting plain error in analogous situations to decide whether plain error exists in the instant case.37 We do so here, and reach the same conclusion.

b.

We need go no further. Without demonstrating error, much less clear or obvious error, Fields cannot satisfy the criteria necessary for our court to grant relief.38

III.

Fields also argues that SORNA's registration requirement is an unconstitutional extension of Congress's Commerce Clause power as interpreted by National Federation of Independent Business v. Sebelius.39 Fields acknowledges that this argument is foreclosed and it is.

In United States v. Whaley, our court held that SORNA was constitutional under the Commerce Clause.40 While Whaley predates National Federation, as we held in United States v. Stager, which addressed the same legal question, this is of no moment:

IV.

We AFFIRM the judgment of the district court.