In a word... no
He doesn't really have a standing. This is an issue that is on a state-to-state level.
At this point, the president has not said he supports legalization of marijuana. In an election year, it is doubtful he would take a stand on such a controversial issue. He has been very honest about his own youthful drug use, but he has not said much about his future plans regarding legalization or decriminalization.
Marijuana not being against the law to have or use anymore. The legalization of marijuana would mean that it's ok for adults to use it and they won't go to jail for it.
Obama's drug "czar" has said that marijuana legalization is a non-starter in his administration. He has said that they would not bother medical users/dispensaries operating withing their respective state laws, however the DEA continues to raid state licensed facilities.
Nothing
At this point in his presidency, he has not come out in favor of legalizing drugs, nor has any other president.
A lot of libertarians do support it because they support liberty & free will. Most politicians who openly support marijuana legalization are either libertarian or liberal.
35%
Never.
THey can't get killed in a drug deal!
Most presidents try to avoid extremely controversial and polarizing issues, especially during an election year. While there are certainly many people (especially young adults) who would like to see marijuana legalized, there are just as many others who are equally strong in their opposition. And among those who are opposed to legalization are many members of law enforcement. Thus, it is doubtful the president will come out in favor of legalization any time soon.
This comes from the White House: "Marijuana legalization for any purpose is a non-starter in the Obama administration." Also "The costs of legalizing marijuana would outweigh any possible tax that could be levied." As for medical marijuana, federally the only thing close to marijuana that you can be prescribed is Marinol which comes in the form of a pill or liquid. Some state governments allow actual marijuana to be prescribed but anyone participating in the use of it, even though prescribed can be punished by federal law. So the answer is no.