If a bill crossed his desk which legalized, decriminalized or rescheduled marijuana, I bet he would sign it. There's an election coming, remember. You can't believe what any of 'em say now (well, always but more now).
I also don't think Obama is a one-termer. While I did vote for him, I am very disappointed in several areas. But the Republicans are just too radical in the changes they want to make.
I do like Ron Paul and would vote for him if he got the nomination. Unfortunately I don't think that is likely but who knows.