To put some numbers on the part of the prison population there for violent offenses:

* Bureau of Justice Statistics says 53% of state prsionsers and 7% (what?!) of federal prisoners (2014): http://www.bjs.gov/content/pub/pdf/p14_Summary.pdf * Federal Bureau of Prisons says 46.5% drug offences (no specification on violent v. non-violent) and 9.2% immigration as the third largest group. Second largest is more violent sounding, though: Weapons, Explosives, Arson 16.9% (2016): https://www.bop.gov/about/statistics/statistics_inmate_offen...

I don't think non-violent crime should always mean no prison, but I suspect there are better ways of dealing with the majority of them.

Also, since you mentioned shorter terms, here are the BOP's numbers of sentence length: https://www.bop.gov/about/statistics/statistics_inmate_sente...