Over at Slate, Ray Fisman breaks down an NBER study on three-strikes laws:
[R]ut yourself in the shoes of a two-strike criminal. The prospect of 25 years behind bars for a third offense is likely to give even a hardened criminal pause before he or she crosses the street against the lights. So we'd expect two-strike felons to commit fewer crimes. But suppose you've already decided to break the law—maybe you need to make a quick buck. Are you going to lift a few golf clubs from the local pro shop? Or are you going to hold up a bank? The potential haul from a bank robbery is obviously much greater, and the penalty is the same: Bank robbery will get you decades in the slammer, but if it's your third offense, so will shoplifting.
Three-strike-eligible criminals who actually do get arrested for a third offense commit more serious crimes. Burglars, for example, become robbers—these are both offenses that involve stealing, but robbery has the added element of force. Similarly, while thefts decline overall, assaults during thefts go up under three strikes, suggesting that an increasing number of thieves may, in desperation, be trying to muscle their way out of a third arrest. In general, arrests of three-strike-eligible felons are 20 percent more likely to be violent crimes (relative to no-strike criminals).
It's tempting to invoke the law of unintended consequences in thinking about what was perhaps a well-intentioned but flawed piece of legislation. But these consequences could have been entirely anticipated if legislators recognized that criminals, like all of us, often make decisions by rationally weighing the costs and benefits of their actions.
Not sure about that last bit–the law of unintended consequences, to the extent that it counts as a "law" at all, is not suspended just because legislators are too slow and invested in tough-on-crime talking points to consider said consequences. It's also worth remembering that prisons are full of people who wasted that last strike on pathetic little victimless crimes and were still slapped with draconian sentences. Matt Welch checked in with California's three-strikes law a few years back:
Pam Martinez…was only recently given clemency from a 25-year sentence for stealing a $30 toolbox. About 4,300 of the 7,000 third-strikers in state prisons were sent there for nonviolent felonies. Of those, The Orange County Register reports, there are "357 people convicted of petty theft, 235 of vehicle theft, 69 of forgery and 678 of drug possession."