Section 921(a)(20) applies to the entire Chapter 44 (§§ 921-931) of title 18. As such, § 921(a)(20) controls 8 U.S.C. § 1101(a)(43), especially subparagraphs (A), (B), (C), (D), (E), (F) and (G). Under § 921(a)(20), Congress says this: "What constitutes a conviction of such a crime shall be determined in accordance with the law of the jurisdiction in which the proceedings were held." This simply means that the federal felony definition controls in all immigration-related cases. More importantly, in § 927 ("Effect on State law"), Congress expressly states: "No provision of this chapter shall be construed as indicating an intent on the part of the Congress to occupy the field in which such provision operates to the exclusion of the law of any State on the same subject matter..." The phrase "provision of this chapter" statutorily covers (among many other crimes) every crime of violence and theft. See also the below section: "Comparison of an aggravated felony to a crime involving moral turpitude".