Obama's most important legislative achievement concerns the issue that prompted my first jot at Jotman: nuclear proliferation. It's one of those issues that is not so high on the public agenda, though it ought to be. Anyway, it turns out that Obama co-sponsored "The Nuclear Non-proliferation and Conventional Weapons Threat Reduction Act." The Lugar-Obama bill as it is also known, eventually became law. Obama said at the time, "The proliferation of weapons of mass destruction is the number one national security threat that confronts the United States today."
Lugar-Obama was partly about keeping shoulder-fire missile launchers out of terrorists' hands -- the fear being that someone will try to take out an airliner. I read somewhere that Obama has a knack for pushing solutions to little-known but important problems, many of which are not politically contentious. For example, Dick Lugar, this bill's co-sponsor is a Republican senator. Many pressing issues are like that I suppose; they are not so contentious, all they lack is a leader with the resolve to push them along.
More: Council on Foreign Relations, the candidates on nuclear non-proliferation