With this last election, as Alaska, Oregon and our nation’s capital joined Washington and Colorado in legalizing marijuana use within their borders. But what about the effects has the legalization of marijuana had on incarceration rates in states where it's been legalized? Will legalization lower prison populations, ease the strain on law enforcement agencies and help lower crime by allowing law enforcement officers to pursue more serious crimes? Here's what we've discovered, looking both nationwide and to our eastern neighbor Colorado, whose legalization of recreational marijuana use made national headlines last fall:Forbes article earlier this year. This is attributed in the Washington Post to a substitution effect, as people substitute marijuana use for alcohol use.