Are victimless criminals pushing out actual criminals???

This is a topic I have only begun to rant about as of late. I was thinking of more effecient arguements for legalising cannabis: trying not to use the medicinal concept (stupid) or the infringement of civil rights (where?). I though about something I haven't heard too much of, actually, I have never heard anything like what I thought of.
Possesion of cannbis is a victimless crime, which accounts for nearly20% of the US's incarcerated population, which hovers right over 2 million. Now, because America's prison are constantly experiencing a large influx of new inmates, room must be made to accomodate the criminals. Many of these new residents are criminals convicted of possesion crimes, or victimless crimes. When these inmates go in, who goes out? I have a theory: actual criminals, some of whom are rapist, pedophiles, wife beaters, etc...
So, is it possible that a backlash from the early release of such criminals to make way for these ticky-tack crime offenders could cause a reformation in the countries drug policy. That is, only if you are angry that Joe-Bob rapist gets an early entrance into society because Freddy McSpliff enjoys smoking after a hard days of work.
So this also calls into question wether anyone is actually angry that such sex offenders are released prematurely (according to the rehabilitation status set for them by society which they are to reenter). If we are, as we say we are, shouldn't we have by now, saught out and eliminated the true culprit for this phenomena: The prohibition of cannabis?