A "Three Strikes and You're Out" law says that a defendant convicted of a third felony must be sentenced to life in prison (though parole may be available after a long time). Generally the felony must be violent or otherwise egregiously nasty. "Three Strikes" laws are also call "habitual offender" or "persistent offender" laws. Such laws have been adopted in over two dozen states.
California: The California Three Strikes law was adopted in a referendum passed November 1994 (Proposition 184), adding Section 1170.12 to the California Penal Code. Most of the Three Strikes Law is Codified in Section 677(b) through (i). The Proposition and Section 677 are posted on the Internet by the California Criminal Law Observer. West publishes a treatise on California Three Strikes Sentencing.
California's Three Strikes law is considered especially harsh because lesser felonies count as strikes (e.g., possession of marijuana by a person in prison). This attracted national attention, especially when judges have tried to soften or avoid the harsh consequences of the law. A Ballot Proposition to permit drug treatment instead of prison in certain cases (Proposition 36) was passed in 2000. A subsequent Ballot Proposition to soften the law further (Proposition 66) was defeated in November, 2004.
Boykin Tahl Rule: The Boykin Tahl Rule is based on two cases, Boykin (395 US 238) and Tahl (1 Cal 3d 122), relating to California's "Three Strikes" law. The rule states that for a guilty plea to be valid a defendant must be advised of four rights:
(1) The right to remain silent;
(2) The right to a jury trial;
(3) The right to confront witnesses; and
(4) If the defendant does not have legal counsel, the right to have counsel.
A defendant can challenge a "Three Strikes" prosecution on the grounds that he or she plead guilty to a felony without being told of all these rights.