在美國，18 U.S.C. § 924(e)為增加刑度的條款，而所增加的刑度為不低於十五年的有期徒刑。其針對的被告為有三次特定類型的犯罪前科記錄的被告，而該特定類型的犯罪為暴力犯或加重毒品犯，或是在觸犯18 U.S.C. § 922(g)（非法持有槍枝罪）的情況下同時成立暴力犯和加重毒品犯。然而，因為此三次犯罪應是在不同的期間內犯下，法院必須要解釋「三次」的意義，以符合§ 924(e)的立法目的。亦即，二次犯罪可能在接近的時間發生，而此二次犯罪是否視為一次或二次即是法院要判斷的議題。本文以一件聯邦第九巡迴上訴法院的判例United States v. McElyea,158 F.3d 1016 (9th Cir. 1998)，來探討該法律解釋是如何地被操作的。結論是「三次」的定義會依照被告在每個地點犯罪時所花的時間與其時序來判斷。

In the United States, 18 U.S.C. section 924(e) provides an enhanced sentence of not less than fifteen years imprisonment for a person who has three previous convictions for a violent felony or a serious drug offense, or both, if such person violates 18 U.S.C. section 922(g) which bans unlawful gun possession. However, because the three previous convictions should have been “committed on occasions different from one another,” courts have to decide what “three” is for the purposes of section 924(e). This article discusses a federal case decided by the Ninth Circuit, United States v. McElyea, 158 F.3d
1016 (9th Cir. 1998), to show how the interpretation is operated. It is concluded that what is “three” might rely on the time sheet of how long a defendant took on each location where crimes happen.