DOMA, Full Faith & Credit, and Criminal History

Under Rhode Island law, a plea of nolo contendere in state court followed by a period of simple probation "shall not constitute a conviction for any purpose." R.I. Gen. L. sec. 12-18-3(a). But when a Rhode Island defendant is charged with a new offense in federal court, the federal sentencing judge will not abide by that statute but will treat any prior Rhode Island "nolo/probation" as a prior conviction because the federal sentencing guidelines ignore state definitions and include all nolo pleas (regardless of sentence) within the definition of "convicted of an offense." 2012 U.S. Sentencing Guidelines Manual, sec. 4A1.2(a). If SCOTUS holds that DOMA is unconstitutional in that Congress could not ignore state definitions of marriage, then why can federal sentencing law -- or immigration law -- ignore state definitions of "conviction?"