The definition of the crime of violence aggravated felony for immigration purposes is set out at 18 U.S.C. § 16:

 

(a)       an offense that has as an element the use, attempted use, or threatened use of physical force against the person or property of another, or

(b)       any other offense that is a felony and that, by its nature, involves a substantial risk that physical force against the person or property of another may be used in the course of committing the offense.[104]

 

Whether an offense is a crime of violence under § 16(a) is usually clear: the offense as defined in the criminal statute of conviction must contain as an essential statutory element the use or threat of physical force against person or property.[105]  The controversy concerning which offenses should be considered crimes of violence has usually centered on the definition of the term under § 16(b), a felony involving the “substantial risk” that physical force may be “used” for the commission of the offense.

 

            Since this is a criminal, rather than an immigration, statute, the federal courts do not defer to the Board of Immigration Appeals in its interpretation.[106]

[104] 18 U.S.C. § 16 (emphasis supplied).

[105] United States v. Reve, 241 F.Supp.2d 470 (D.N.J. Jan. 31, 2003) (New Jersey conviction of sexual assault, defined as committing an act of sexual penetration with a victim who is at least thirteen but less than sixteen years old and the actor is at least four years older than the victim, in violation of former N.J.S.A. § 2C:14-2(c)(5) (1995), recodified, N.J.S.A. § 2C:14-2(c)(4) (Supp. 2002), did not constitute an aggravated felony crime of violence, because the offense did not have as an element using, attempting to use, or threatening to use force against the victim, as required by 18 U.S.C. § 16(a); government did not argue substantial risk under 18 U.S.C. § 16(b)).

[106] See § 2.19, supra.

Ninth Circuit

AGGRAVATED FELONY - CRIME OF VIOLENCE - ASSAULT WITH FIREARM
United States v. Pintado-Isiordia, ___ F.3d ___ (9th Cir. May 26, 2006) (per curiam) (because record unclear whether district court relied on categorical approach, or modified categorical approach, defendants sentence for illegal reentry was vacated and remanded for district court determination as to whether prior conviction for assault with a firearm qualifies as a "crime of violence" under either approach).
http://caselaw.lp.findlaw.com/data2/circs/9th/0550489p.pdf