What will happen is prisons will be full of people convicted of other crimes.<p>In some sense, prison capacity limits prison population (notwithstanding unconstitutional overcrowding, which has its own limit). If the prisons were emptied of marijuana convictions, then that would free up space for other convictions.<p>So maybe the way to reduce the prison population is to close some prisons. Not everyone convicted needs to be in prison, and not everyone caught needs to be prosecuted.