They half succeeded in creating South Korea. They succeeded in Iraq, which I like to always point out because that war is often cited as a "loss" for the US. Mostly because Bush declared it over when it was really just beginning.
Really hard to say what will happen with Iran. Everyone online likes to act like military prophets that know the future, but truthfully it's very difficult to predict imo. And what does happen depends probably on how deep the US invests into it. If they start sending troops in to invade, then that obviously changes things.