摘要：Every now and then a case ·comes along that tests the fundamental premises of a body of law. United States v. DiFrancesco presents such a test to the law of double jeopardy, raising the question whether the government may unilaterally appeal a defendant's criminal sentence for the purpose of increasing the sentence. The question cannot be answered by facile reference to the text of the fifth amendment, because the terms of the double jeopardy clause are not self-defining. Nor can it be settled by reference to history, because the issue has not arisen with any frequency until now.
