Closing the door on diplomacy would essentially lead to war ? but what kind of war

A White House official is quoted as saying that "given a choice between 'total capitulation' and advancing toward a nuclear weapon, Iran would choose the weapon,

That posture, according to this diplomat, would “close the door on diplomacy” and would “essentially lead to war.” 

One can only wonder about the spokesman's logic: 

1. He states that Iran is committed to the idea of developing nuclear weapons to such an extent,   that forcing the country to give up the idea completely would push the Iranians to end the negotiations. 
2. And yet, he wishes to convince anyone that the negotiations are going to remove the risk of a nuclear weapons armed race in the middle east ? After all, if Iran is that committed to this idea, is it really such a good idea to reach a compromise, which brings along at its end, a nuclear Iran ? 
3. Furthermore, which situation is preferred, in the eyes of the aforementioned official - a war in which Iran is not armed with nuclear weapons, or a war in which Iran is ? 

Sometimes, even if you doubt Israel Prime Minister's diplomatic strategy, you just have to give it to him - U.S officials do sound a lot like a certain English Prime Minister, shortly before World War II, promising peace in our time.