I don’t think foreign policy, Circa 2014, is a Libertarian vs Conservative issue. It’s an issue of American exceptionalism vs Postmodernism. The Iraq war was going pretty well when a regime who believed in American exceptionalism was in charge. When the Postmodernists took over, every gain was quickly dissolved. The realism factor is not what Stossel thinks. The disaster that is Iraq is not a necessary function of war, it’s what happens when there’s no moral impetus to win. Which demonstrates why I’m not a Libertarian. They preach a political paradigm devoid of moral considerations.
War with Iran would be an unimaginable disaster, but not because it violates some Libertarian philosophy.
Foreign policy in 2014 should involve narrowly identifying our interests, then defending those interests.