OPINION OF THE COURT
The government brings this appeal challenging the District Court’s ruling that a prior conviction for wearing body armor while committing a felony in violation of 11 Del. C. § 1449(a) is not a predicate offense under the Armed Career Criminal Act (“ACCA”), 18 U.S.C. § 924(e). We hold that the body armor conviction is an ACCA predicate offense because it involved the possession of cocaine with intent to distribute. It is “a serious drug offense.” 18 U.S.C. § 924(e)(1). We will vacate the ruling of the District Court and remand for sentеncing in conformity with this opinion.
I.
Under 18 U.S.C. § 922(g)(1), it is unlawful for a felon to possess a firearm. A person convicted under this section is subject to a fifteen-year sentence-enhancement provision:
(1) In the case of a person who violates section 922(g) of this title and has three previous convictions by any court referred to in section 922(g)(1) of this title for a violent felony or a serious drug offense, or both, committed on occasions different from one аnother, such person shall be fined under this title and imprisoned not less than fifteen years, and, notwithstanding any other provision of law, the court shall not suspend the sentence of, or grant a probationary sentence to, such person with respect to the conviction under section 922(g).
(2) As used in this subsection—
(A) the term “serious drug offense” means' — ■
(i) an offense under the Controlled Substances Act (21 U.S.C. 801 et seq.), the Controlled Substances Import and Export Act (21 U.S.C. 951 et seq.), or chapter 705 of title 46, for which a maximum term of imprisоnment of ten years or more is prescribed by law; or
(ii) an offense under State law, involving manufacturing, distributing, or possessing with intent to manufacture or distribute, a controlled substance (as defined in section 102 of the Controlled Substances Act (21 U.S.C. 802)), for which a maximum term of imprisonment of ten years or more is prescribed by law;
(B) the term “violent felony” means any crime punishable by imprisonment for a term exceeding one year, or any act of juvenile delinquency involving the use or carrying of a firearm, knife, or destructive device that would be punishable by imprisonment for such term if committed by an adult, that—
(i) has as an element the use, attempted use, or threatened use of physical force against the person of another; or
*183 (ii) is burglary, arson, or extortion, involves use of explosives, or otherwise involves conduct that presents a serious potential risk of physical injury to another; ....
18 U.S.C. § 924(e).
Leonard Gibbs was arrested fоr violating the conditions of his probation. In the course of arrest, the police discovered a loaded .357 caliber revolver with ammunition. He was charged with two counts: knowing possession of a firearm and knowing possession of ammunition after having been previously convicted of a felony, in violation of 18 U.S.C. §§ 922(g)(1) and 924(a)(2). Gibbs pled guilty to the firearm count pursuant to a plea agreement, which stated that “[t]he maximum penalties for this offense are 10 years [of] imprisonment” and that the government agreed to move to dismiss the ammunition count. The District Court accepted Gibbs’ guilty plea.
After the guilty plea but before Gibbs’ sentencing, the government changed its position. The government explained that, after reviewing the pleadings from Gibbs’ previous convictions, it concluded that Gibbs had three prior felonies meeting the requirements for an enhancement under the ACCA. By the government’s count, the three § 924(e) “violent felony or a serious drug offense” convictions included a 2003 conviction for “aggravated menacing,” a 2004 conviction for possession with intent to deliver cocaine, and a 2007 conviction in Delaware state court for wearing body armor while committing a felony. There was no dispute that the first two convictions are ACCA predicate offenses, but the government changed its position with respect to the 2007 conviction.
The government argued that wearing body armor while committing a felony was a serious drug offense under § 924(e) because the underlying felony was possession with intent to distribute cocaine. After Gibbs’ guilty plea but before the sentencing hearing, the government informed Gibbs in a letter of its revised position. No longer did the government subscribe to its view in the plea agreement that “[t]he maximum penalties for this offense are 10 years [ofj imprisonment.” As a result, the government stated, it would not oppоse a motion by Gibbs to withdraw his guilty plea before sentencing. But if Gibbs wished to proceed, the government would argue for the imposition of an enhanced sentence under the ACCA. Gibbs decided to proceed to sentencing, where he would argue that the body armor conviction was not an ACCA predicate offense.
At the sentencing hearing, the government argued that the District Court must take a closer look at Gibbs’ 2007 conviction. The indictment charged him with two сounts. The first stated that Gibbs “did knowingly wear body armor during the commission of a felony, Possession with Intent to Deliver Cocaine, as set forth in Count II of this indictment which is incorporated herein by reference.” (App. at 28.) Count II charged that Gibbs “did knowingly and unlawfully possess Cocaine ... with the intent to deliver same,” in violation of 16 Del. C. § 4751. (Id. at 28-29.) Gibbs pled guilty to the first count but not the second. In doing so, he engaged in the following colloquy:
The Court: You are charged that on or about the 21st day of Oсtober 2006, in the County of New Castle, State of Delaware, you did knowingly wear body armor during the commission of a felony, the felony being Possession with Intent to Deliver Cocaine, in violation of Title 11 of the Delaware Code. Do you understand the crime as I’ve read it to you?
The Defendant: Yes, ma’am.
The Court: And how do you plead?
The Defendant: Guilty.
*184 (Id. at 51-52.) The government argued that, though Gibbs was not convicted of the drug charge, the body armor conviction was a serious drug offense.
After considering. the government’s changed position, the probation office released a revised presentence report concluding that Gibbs was not subject to an ACCA enhancement. The government objected, and the District Court .ruled in Gibbs’ favor. 1 The Court stated that it could only look to the text of the statute and the fact of conviction. The Delaware body armor statute proscribes a person from “wear[ing] body armor during the commission of a felony.” 11 Del. C. § 1449. The statute does not limit the underlying “felony” to drug-related felonies. The District Court concluded that “the substantive content of [Delaware’s body armor statute] does not qualify it as a serious drug crime under the ACCA,” (app. at 71) and held that Gibbs was not subject to the § 924(e) enhancement. The Court sentenced Gibbs to 72 months’ imprisonment, and the government timely appealed.
II.
The District Court had jurisdiction under 18 U.S.C. § 3231. We have appellate jurisdiction under 28 U.S.C. § 1291 and 18 U.S.C. § 3742. We review the District Court’s denial of the ACCA enhancement de novo because the government’s appeal raises a pure question of law.
United States v. Henton,
III.
The government appeals the District Court’s ruling that Gibbs’ state body armor conviction is not an ACCA predicate offense. We start with the text of the ACCA. A state conviction qualifies as “a serious drug offense” if it is an offense “involving manufacturing, distributing, or possessing with intent to manufacture or distribute, a controlled substance (as defined in section 102 of the Controlled Substances Act (21 U.S.C. 802)), for which a maximum term of imprisonment of ten years or more is prescribed by law.” 18 U.S.C. § 924(e)(2)(A)(ii). There is no dispute that Gibbs’ body armor conviction carried a maximum term of imprisonment of ten years or more, see 11 Del. C. §§ 1449 and 4205(b)(2) (carrying a statutory maximum of 25 years imprisonment). The issue is whether- the body armor conviction “involv[ed]” manufacturing, distributing, or possessing, with intent to manufacture or distribute, a controlled substance.
Congress’s use of the term “involving” expands the meaning of a serious drug offense beyond the simple offenses of manufacturing, distributing, and possessing a controlled substance.
See, e.g., United States v. James,
Gibbs argues that § 924(e)(2)(A)(ii), defining the state offenses that arе serious drug crimes, should be interpreted in light of § 924(e)(2)(A)®, defining the federal offenses that are serious drug crimes. Section 924(e)(2)(A)® defines serious federal drug offenses by reference to three statutes: the Controlled Substances Act, 21 U.S.C. § 801 et seq.; the Controlled Substances Import and Export Act, 21 U.S.C. § 951 et seq.; and the Maritime Drug Law Enforcement Act, 46 U.S.C. §§ 7501-70508. Gibbs argues that the definition of state serious drug offenses should be limited to the types of crimes identified by the three federal statutes. In other words, Gibbs argues thаt subsection (ii) cannot include a broader range of offenses than subsection (i).
While both subsections relate to the same subject, there is no reason to think that subsection (i) should limit our construction of subsection (ii). If Congress wished to do this, it could have done so. In the federal “three strikes” law, 18 U.S.C. § 3559(c), Congress limited the definition of serious state drug crimes by defining it as, “an offense under State law that, had the offense been prosecuted in a court of the United Statеs, would have been punishable under section 401(b)(1)(A) or 408 of the Controlled Substances Act (21 U.S.C. 841(b)(1)(A), 848) or section 1010(b)(1)(A) of the Controlled Substances Import and Export Act (21 U.S.C. 960(b)(1)(A)).” 18 U.S.C. § 3559(c)(2)(H)(ii). -Congress explicitly limited the serious state drug offenses to the serious federal drug offenses. The ACCA did not take this approach. Instead, Congress used broad terminology— “involving” — to define the category of serious state drug offenses without limiting its scope to federal statutes. This means that Congress did not wish subsectiоn (ii) to be limited to the same set of crimes listed in subsection (i).
Congress adopted a broad interpretation of “a serious drug offense” because it inténded to define an “entire class of state offenses ‘involving’ certain activities, namely, ‘manufacturing, distributing, or possessing with intent to manufacture or distribute’ a controlled substance.”
Alexander,
Congress used the term “involving” to carve the class of serious state drug crimes broadly. But there are of course limits to how wide we can construe this class. As the First Circuit noted, “[n]ot all offеnses bearing any sort of relationship with drug manufacturing, distribution, or possession with intent to manufacture or distribute will qualify as predicate offenses under ACCA. The relationship must not be too remote or tangential.”
McKenney,
Of critical importance is what approach wе take to this question. The District Court held that it could only examine the Delaware statute and the fact of conviction, thereby precluding an examination of the underlying indictment and plea colloquy. The government argues that we should adopt an approach that allows us to look to the underlying indictment and plea colloquy. The former approach has been termed the “formal categorical approach” and thе latter the “modified categorical approach.” Before we proceed, we must determine which approach is applicable in this case.
The ACCA generally requires that the sentencing court look only to the fact of conviction and not to the facts underlying the conviction.
Taylor v. United States,
Such a reading of the ACCA makes sense. Congress wished to avoid an approach allowing an examination of the underlying facts that “could force sentencing courts to hold mini-trials, hear evidence and witnesses and otherwise engage in a detailed examination of specific facts involved in the prior offense.”
United States v. Preston,
In recognition of the need to look beyond the mere fact of conviction in some cases, the Supreme Court developed the modified categorical approach to allow sentencing courts to look at the indictment or information and the jury instructions.
Taylor,
For еxample, in a State whose burglary statutes include entry of an automobile as well as a building, if the indictment or information and jury instructions show *187 that the defendant was charged only with a burglary of a building, and that jury necessarily had to find an entry of a building to convict, then the Government should be allowed to use the conviction for enhancement.
Id.
The modified categorical approach is not limited to prior violent felonies but also applies to determine whether a prior conviction was a serious drug offense.
See Vickers,
[The modified categorical approach] applies in cases where the state statute can be violated in several different ways, some of which would support enhancement under 924(e) and some of which would not. In those cases, the sentencing court may examine the indictment, other charging papers, or jury instructions to determine whether the defendant was charged with a crime that meets the requirements of section 924(e).
The Delaware body armor statute “can be violated in several different ways.”
Id.
The statute merely proscribes a person from wearing body armor “during the commission of a felony,” 11 Del. C. § 1449, but it leaves the underlying felony undefined. This use of the word “felony” incorporates by reference the disjunctive list of all felonies. We cannot determine from the face of the statute alone whether a violation is an ACCA predicate offense but must look to the underlying facts of the conviction to determine if it is a violent felony or a serious drug offense. If the underlying felony was burglary, a violation of the body armor statute may constitute a violent felony. Likewise, if the underlying felony was manufacturing, distributing, or possessing a controlled substance, this may constitute a serious drug offense. In order to determine whether the body armor conviction is an ACCA predicate offensе, one must look to the charging instrument or jury instructions. Applying the modified categorical approach in this context does not entail an “elaborate fact-finding process regarding the defendant’s prior offenses,”
Taylor,
*188 Under the modified categorical approach, we examine the indictment to find that the body armor charge states that Gibbs “did knowingly wear body armor during the commission of a fеlony, Possession with Intent to Deliver Cocaine, as set forth in Count II of this indictment which is incorporated herein by reference.” (App. at 28.) We must determine whether Gibbs’ offense as stated in the indictment meets the ACCA’s definition of a serious drug offense. The question then becomes whether wearing body armor while committing a felony, where that felony is possession of cocaine with intent to distribute, is related to or connected with “manufacturing, distributing, or possessing with intent to mаnufacture or distribute, a controlled substance,” 18 , U.S.C. § 924(e)(2)(A)(ii), or if it is too remote or tangential.
To determine whether a conviction is related to or. connected With the particular conduct of manufacturing-, distributing, or possessing a controlled substance, “courts follow the approach outlined in
Taylor
and ask whether the proscribed conduct is an inherent part or result of the generic crime of conviction ... or, stated somewhat differently, whether the abstract crime intrinsically involves the proscribed conduct.”
Brandon,
First, the underlying felony is an inherent part of the offense of wearing body armor while committing a felony because the underlying felony must be proven in order to be guilty of the body armor offense. 'While it is true that the defendant need not be convicted of a drug offense, a person convicted under 11 Del. C. § 1449 has to be found guilty of some underlying felony. And where, as in this case, the felony is a drug crime, proof of the elements of a drug offense is required.
See Priest v. State,
Gibbs argues that this interpretation of “a serious drug offense” raises a constitutional problem of fair notice. But our case law holds that a statute “violates due process of law if it ‘either fоrbids or requires the doing of an act in terms so vague that men of ordinary intelligence must necessarily guess as to its meaning and differ as to its application.’ ”
United States v. Woods,
IV.
We hold that Gibbs’ body armor conviction is an ACCA predicate offense. The government argues that we need not remand to the District Cоurt for a determination of whether the ACCA enhancement is in conformity with the terms of Gibbs’ plea agreement. We disagree and believe there are material issues of fact that the District Court must resolve. For the foregoing reasons, we will vacate and remand to the District Court to rule on Gibbs’ outstanding objection to the ACCA enhancement.
Notes
. Gibbs objected that an ACCA enhancement was inconsistent with' the terms of the plea agreement. The District Court did . not rule on this objection because it held that the enhancement did not apply.