ult and execution may issue thereon." Fed. R. Crim. P. 46(e)(31. A judgment for the government is en forced by the Financial Litigation Unit under the Federal Debt Collection Procedu res Act of 1990. See 28 U.S.C. S 3201-3206 (relating to government's "postjudgm ent remedies"). If the defendant reappears "(a)fter entry of suc h