The title says it all, the laws in this country seem to be very conflicting between federal and state laws. This shouldn't be the case, federal law should at least give the states the right to choose in the eyes of the federal government. In a perfect world, it would be legalized to the points states can't outlaw possession or arrest for cannabis possession. Leaving it up to the states to decide if they wish to allow the sale or not, with the latter costing them massive amounts in tax revenue to pay for other important things such as education and transportation infrastructure.
It's coming to a point that states are in a deficit because of their failed policy to keep it illegal when polls show a majority of American citizens support legalization of recreational, while a super majority support medical legalization. It's time to get away from the Reefer Madness days that prohibitionists seem stuck in. It's a public health crisis, not a criminal crisis.