Decriminalizing pot at the federal level won't make it legal. It really wouldn't make much difference at all since most simple possession arrests are not made by federal officers under federal law. Decriminalization just means taking the threat of jail away. Several states have decriminalized pot. They just fine people for it. In most states that have decriminalized it is no longer a criminal offense, not a misdemeanor or felony anymore. It's a “violation” or an “infraction,” and people are just ticketed for it like they would be for a speeding violation. It is not legal though. And the bottom line is that per capita marijuana use in states that have decriminalized it is about the same as it is in states that haven't decriminalized it. In the grand scheme of things it really doesn't make any difference in the number of users whether possession of a small amount is a “violation” or “civil infraction” or a misdemeanor crime.