The authors conclude that the intent of "three strikes" laws--namely, to increase the incapacitation period for habitual, dangerous offenders and thus reduce the level of violent and serious crime--has not been achieved after almost a decade and a half. Although it may still be too early to make a final judgment on the effectiveness of these laws, what is needed are more studies to determine whether such laws are having their intended effects; and if not, whether they should be modified or abolished. This paper traces the legal history and court rulings regarding habitual-offender and three strikes laws, followed by a review of current pertinent legislation, with attention to variations in State and Federal laws. A review of research on the impact of such laws does not show as many "three strikers" in the prison population as originally projected. This is due largely to prosecutors' and judges' use of their discretion to dismiss prior "strikes" and the use of diversion programs for drug offenders. According to a 2003 study by the Justice Policy Institute, of those "three strikers" who are imprisoned for longer periods than a third felony would typically draw, 57 percent were given a 25-years-to-life sentence for a nonviolent third offense. More "third strikers" were serving such a sentence for drug possession than for second-degree murder, assault with a deadly weapon, and rape combined. 62 references