People who claim that they have an alternative to the Iran nuclear deal besides war might want to check in with Wisconsin governor Scott Walker, widely judged to be one of the three "serious" Republican candidates for President.
As Greg Sargent notes at the Washington Post, Walker has previously said that he would undo an Iran deal on the first day of his presidency, regardless of what our allies have to say about it, and now says that "the next president could be called to take aggressive actions, including military action, on the first day in office."
As Sargent noted, Walker didn't specifically say "military action against Iran," but the context of his remarks was a dispute with Jeb Bush about how they would respond as President to the Iran deal. Both of them claim that they would move immediately to undo the deal, but Jeb Bush says that before acting he would first consult with U.S. allies and with his advisers. Walker says that he would be ready to undo the deal on the first day in office. This is the context in which Walker said that he might have to take military action on the first day of his Presidency.