Should sex offenders be released after they have finished their prison terms?

The decision by New York to confine sex offenders beyond their prison terms places the state at the forefront of a growing national movement that is popular with politicians and voters. But such programs have almost never met a stated purpose of treating the worst criminals until they no longer pose a threat.
About 2,700 pedophiles, rapists and other sexual offenders are already being held indefinitely, mostly in special treatment centers, under so-called civil commitment programs in 19 states, which on average cost taxpayers four times more than keeping the offenders in prison.