So does putting more people in jail automatically reduce crime?  Your gut may say yes, but there are some interesting statistics on this matter.  Here is more from the Washington Post on our Incarceration Nation:

The growth in prison population is largely because of tougher state and federal sentencing imposed since the mid-1980s. Minorities have been particularly affected: One in nine black men ages 20 to 34 is behind bars. For black women ages 35 to 39, the figure is one in 100, compared with one in 355 for white women in the same age group.
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For instance, Florida, which has almost doubled its prison population over the past 15 years, has experienced a smaller drop in crime than New York, which, after a brief increase, has reduced its number of inmates to below the 1993 level.
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Many state systems also send offenders back to prison for technical violations of their parole or probation, such as failing a drug test or missing an appointment with a supervisory officer. A 2005 study of California's system, for example, found that more than two-thirds of parolees were being returned to prison within three years of release, 40 percent for technical infractions.

So while prison is an important part of the overall criminal justice system, the New York example clearly shows that there is no direct tie between increased incarceration, and decreased crime.  It is in fact possible to decrease crime, and not throw the world in jail.  It means we need to be smarter about who we incarcerate, and the crimes which we choose to go after.  The problem with this country is that we're so obsessed with passing laws, that its nearly impossible to stay a law abiding citizen.  If someone wants to throw you in jail for some reason, they can... they'll just have to do a bit of research to figure out what you did wrong.