Sometimes you're left with no choice. Iran has been directly, and indirectly, responsible for hundreds of American deaths over the years. When a country whose main objective is to your demise and he of your allies is close to being able to make a nuclear weapon, sometimes you have to do certain things.
And you speak of one man getting us into all this BS. Congress hasn't declared war since WWII and hasn't authorized military force since 2002. Clinton had no authorization for Kosovo. Obama had no authorization for Libya when Gaddafi was overthrown.
