*421 OPINION
Jeffrey Ford challenges his sentence for bank robbery, arguing that the district court improperly sentenced him as a career offender under § 4Bl.l(a) of the sentencing guidelines. Because his previous conviction for a “walkaway” escape is not a “crime of violence” under this provision of the guidelines, we reverse and remand for resentencing.
I.
In 2007, Ford pleaded guilty to bank robbery. See 18 U.S.C. § 2113(a). The district court calculated an advisory guidelines range of 151 to 188 months, see U.S.S.G. ch. 5, pt. A, and sentenced Ford to 151 months. His offense level included a 10-point career-offender enhancement based on his present bank-robbery conviction and prior state-law convictions for robbery and second-degree escape. See id. § 4Bl.l(a).
II.
Ford’s appeal presents one issue: Does his prior conviction for escape constitute a “crime of violence”?
Some of this ground is well-plowed. A defendant is a career offender, as pertinent here, if he was at least 18 when he committed the offense, the offense is a felony “crime of violence” and he has been convicted of at least two prior felony “crime[s] of violence.” Id. § 4Bl.l(a). A “crime of violence” is an offense that warrants at least a year in prison and that “(1) has as an element the use, attempted use, or threatened use of physical force against the person of another, or (2) is burglary of a dwelling, arson, or extortion, involves use of explosives, or otherwise involves conduct that presents a serious potential risk of physical injury to another.” Id. § 4B 1.2(a).
Acknowledging that his robbery convictions — his present one and his earlier one — amount to crimes of violence, Ford argues that his second-degree-escape conviction does not. That type of conviction, everyone agrees, does not contain a use-of-force element, and it is not a burglary-of-a-dwelling, arson, extortion or use-of-explosives offense. That leaves the possibility that the offense “otherwise involves conduct that presents a serious potential risk of physical injury to another.”
Id.
Two inquiries guide our application of the residual clause. One, does the crime present a serious potential risk of violence akin to the listed crimes?
See James v. United States,
In answering these questions, we treat a “crime of violence” under § 4Bl.l(a) of the guidelines the same as a “violent felony” under the Armed Career Criminal Act, 18 U.S.C. § 924(e)(1);
see United States v. Houston,
Kentucky criminalizes several types of “escape.” Ford was spared the first one— first-degree escape — which covers “escapes from custody or a detention facility by the use of force or threat of force against another person.” Ky.Rev.Stat. § 520.020(1). Yet he was convicted of second-degree escape, a broadly worded offense that covers any other “escapef ] from a detention facility” or “eseape[ ] from custody” by an individual “charged with or convicted of a felony.” Id. § 520.030(1). To violate this provision, one need only leave “when the departure is unpermitted” or fail to return “following a temporary leave granted for a specific purpose or for a limited period.” Id. § 520.010(5). A “detention facility” includes “any building ... used for the confinement of a person: (a) Charged with or convicted of an offense; (b) Alleged or found to be delinquent; (c) Held for extradition or as a material witness; or (d) Otherwise confined pursuant to an order of court.” Id. § 520.010(4). And “custody” includes any “restraint by a public servant pursuant to a lawful arrest, detention, or an order of court for law enforcement purposes,” excluding only “supervision of probation or parole or constraint incidental to release on bail.” Id. § 520.010(2). (Kentucky also has a third-degree offense not relevant here, which applies to individuals, regardless of their charged or convicted offenses, who “escapef ] from custody.” Id. § 520.040.)
All said, a conviction for second-degree escape covers everything from a felon who breaks out of a maximum-security prison to one who fails to report to a halfway house. The crime at hand — a “walkaway” escape, U.S. Letter Br., Feb. 10, 2009, at 2 — falls somewhere in between.
Under Sixth Circuit law at the time of Ford’s sentencing, as the district court correctly recognized, a “walkaway” escape constituted a crime of violence. In
United States v. Bailey,
Since then, however, the Supreme Court decided
Chambers,
which held that one type of escape conviction under Illinois law — a “failure to report for penal confinement”' — -is not a “violent felony” under the Armed Career Criminal Act.
Chambers
modifies circuit law. Until now, we have taken the view that all escape offenses — from a failure to report at one end of the spectrum to a breakout at the other — constitute crimes of violence.
See Bailey,
Chambers,
it seems to us, also undermines the notion that a “walkaway” conviction is a crime of violence. In the context of the Illinois law at issue, it is true,
Chambers
appeared to divide escape convictions into just “two separate crimes, namely escape from custody on the one hand, and a failure to report on the other.”
If under Illinois law there were “at least two” ways to characterize an escape conviction in
Chambers,
there are
at least three
ways to characterize an escape conviction under Kentucky law. In addition to proscribing general departures from custody and general failures to return, Kentucky law separately criminalizes escapes involving “the use of force or threat of force against another person,” and Kentucky law separately treats the offense as a first-degree offense. Ky.Rev.Stat. § 520.020(1);
see Chambers,
We think so.
First,
it is not lost on us that the categorical approach requires courts to pick the right label, and “sometimes the choice is not obvious.”
Chambers,
Second,
in the aftermath of
Chambers,
a “walkaway” is a meaningfully distinct and meaningfully distinguishable category of escape as a matter of federal law. No doubt Kentucky’s broadly worded definition of second-degree escape does not separate walkaways from other escapes. But neither does it separate failures to report from departures from custody. If
Chambers
permits the federal courts to treat failures to report as separate offenses under Illinois law, it would seem to permit them under Kentucky law, whether the state statute separately describes them or not, because the end-game question is whether the offense is a “crime of violence,” U.S.S.G. § 4B1.2(a), which is a matter of federal, not state, law. Much as failures to report to custody represent a distinct form of escape, moreover, so do walkaways. There is a difference between individuals who overcome physical barriers to freedom and those who walk off the grounds — those in other words who leave a facility without removing a physical restraint, without breaking a lock on a door, without climbing over a prison wall or security fence or without otherwise breaking through any other form of security designed to keep them put.
See Templeton,
Third,
a walkaway escape does not present the
risk
of physical injury to others that the listed crimes of violence do. No one in this case has offered any empirical evidence suggesting that walkaway escapes, in contrast to traditional escapes, are apt to lead to serious risks of physical injury. And the one court to our knowledge to look into the issue, the Seventh Circuit, found that they have no such risk.
Templeton,
Fourth,
walkaway offenses do not involve the same
type
of “purposeful, violent, and aggressive” conduct that the listed crimes of violence do.
Id.
(internal quotation marks omitted). No doubt, all walkaway offenders have engaged in purposeful conduct. After that, however, there is nothing in the statute that requires the offense to involve purposeful violence or purposeful aggressiveness. All that the Kentucky statute requires is a “departure” that is “unpermitted,” Ky.Rev.Stat. § 520.010(5), and it defines the “detention facility” from which the departure occurs as “any building ... used for the confinement of a person,”
id.
§ 520.010(4). A walkaway does “not involve ‘aggressive’ conduct against either a person (as in extortion) or property (arson). All the [law] requires is that the escapee leave.”
Templeton,
Fifth,
if any doubt remains about this conclusion, the rule of lenity alleviates it. When ambiguity clouds the meaning of a criminal statute, “the tie must to go the defendant.”
United States v. Santos,
— U.S. —,
In our seminal rule-of-lenity decision, Chief Justice Marshall rejected the impulse to speculate regarding a dubious congressional intent. “[Probability is not a guide which a court, in construing a penal statute, can safely take.” United States v. Wiltberger,5 Wheat. 76 , 105,5 L.Ed. 37 (1820). And Justice Frankfurter, writing for the Court in another case, said the following: “When Congress leaves to the Judiciary the task of imputing to Congress an undeclared will, the ambiguity should be resolved in favor of lenity.” Bell v. United States,349 U.S. 81 , 83,75 S.Ct. 620 ,99 L.Ed. 905 (1955).
Santos,
*426 * :]: *
To recap: the first question in this case — the Taylor question — is whether the definition of the state-law offense by itself establishes that it is a “crime of violence.” A conviction for second-degree escape does not show that Ford committed a crime of violence because the offense covers a variety of escapes, some of which (a failure to report and to return, at least) are not crimes of violence. The second question— the Shepard question — is whether the government nonetheless can show that the state-law conviction was a crime of violence by bringing forward reliable documents from the underlying conviction that “necessarily” establish that the defendant committed a crime of violence. Here, the parties agree, reliable documents show that Ford committed a “walkaway” escape, which no doubt may create a greater risk of physical injury than a failure to report, but which remains different from a jailbreak and other crimes of violence both in kind and in its risk of physical injury to others. For these reasons and those elaborated above, a walkaway is not a crime of violence.
In reaching this conclusion, we note that the government does not oppose it. In the aftermath of
Chambers,
the government concedes that Ford’s walkaway offense does not amount to a crime of violence, “retreat[ing] from its prior position that walkaway escapes are violent felonies.” Letter Br., Feb. 11, 2009 at 1 (internal quotation mark and alteration omitted). That concession is not dispositive because a party’s position in a case (even when that party is the United States) does not dictate the meaning of a federal law,
cf. Hohn v. United States,
III.
For these reasons, we reverse and remand for resentencing.
