Matter of Velazquez-Herrera, 24 I. & N. Dec. 503, ___ (BIA May 20, 2008) ("Our analysis is further influenced by the presumption that the Federal immigration laws are intended to have uniform nationwide application and to implement a unitary Federal policy. Kahn v. INS, 36 F.3d 1412, 1414 (9th Cir. 1994) (citing Mississippi Band of Choctaw Indians v. Holyfield, 490 U.S. 30, 43-44 (1989)). Therefore, absent clear congressional guidance to the contrary, the meaning of the term "crime of child abuse" will be determined by reference to a "flexible, uniform standard that reflects the federal policies underlying" section 237(a)(2)(E)(i) of the Act, and not by reference to legal classifications that vary from State to State. Kahn v. INS, supra, at 1414-15; see also Matter of Rodriguez-Rodriguez, 22 I&N Dec. 991, 995 (BIA 1999).").