[throwaway_5633]

Longer incarceration times in the US, fewer alternative punishments, lower rehabilitation and a higher inequality compared to similar countries. Recidivism in North-west Europe is around 25% compared to around 60% for the US, combined with longer and more prison sentences for comparable crimes quickly leads to much higher incarceration rates.

[metalcrow]

Longer incarceration times and lower rehabilitation (and lack of interest in it) are definitely huge ones you're right.