Why should marijuana be legalized?

I will be writing a persuasive speech on the legalization of marijuana in the next couple of days for my final grade in a college speech cl. My belief is that marijuana should be legalized in the United States, as long as there are limitations and governmental guidelines. Can anyone think of a thesis statement that has three points that covers this topic area? I am having trouble coming up with three specific reasons for legalization. "Marijuana should be legalized because.. a:_____ b:_____ c:_____"