There is confusion over the current status of marijuana usage across some states that have declared it legal. And the various state laws that have passed have created a variety of interpretation. We need to establish a national uniform set of laws to govern the use and sale of marijuana as well as a standard for the marijuana growers.
Many people use marijuana to relieve the pain of chronic illness. It would be unfair for someone to be allowed to do this legally in one state while their friends in a neighboring state are banned from doing so. Also, with so many people traveling freely between and across states it would be very difficult for individuals to remember which states have legalized the use of the drug.
Yes, marijuana should be legalized on a national level. The current patchwork is bizarre and merely creates unjustified "criminals" that burden the legal system for no reason. Settling the matter once and for all allows uniform substance abuse programs funded by the sales tax of marijuana. It also allows cross-state sales of buds and growing equipment which stimulates the economy. Finally, it frees up law enforcement to focus its effort on stopping truly dangerous drugs like heroin and meth.
Individual states should decide whether or not to legalize marijuana. Yes, the federal government can stop prosecuting non-violent drug crimes, but it should not force states to legalize marijuana. Once states that do legalize see a drop in crime and an increase in tax revenue, other states will follow suit by legalizing pot as well.