Obama says he's not ruled out using military force, but he has not been so directly threatening. Romney takes a far harder line and says he would stand much closer to Israel.
As if to draw a line under his Iran policy, Romney said in one Republican debate: "If we re-elect Barack Obama, Iran will have a nuclear weapon. And if we elect Mitt Romney, if you elect me as the next president, they will not have a nuclear weapon."
In U.S. presidential elections, it remains axiomatic that a candidate trying to win a party's nomination plays more to the extremes when seeking a place on the ballot and then charts a more moderate course in the final election campaign. Even at that, however, history teaches that it often is far easier to make campaign promises than to fulfill them once in office.
Just ask Obama, who vowed he would close the U.S. military prison for terrorist suspects at Guantanamo Bay, Cuba, during his first year in office. That still hasn't happened — Congress has stood in the way of such action — and the pledge lives on mostly as an issue the Republicans use against the president."