The question in the Situation Room that day: What would happen if Obama publicly committed to a war to keep Iran from getting a nuclear weapon?

Obama had never made such a promise in public, and he thought it would help persuade Netanyahu to step back from the brink. But by speaking out, he would be putting the U.S.’s credibility on the line in the global effort to prevent Tehran from getting a weapon. If he promised to go to war and didn’t follow through, other nations in the region, distrusting American assurances of protection, would start their own nuclear programs. Obama said that he was aware of the risk but that he wanted to draw the line in public anyway. On March 4, 2012, Obama told the AIPAC crowd, “I will not hesitate to use force when it is necessary to defend the United States and its interests.” In his interview with Jeffrey Goldberg of the Atlantic, he said, “As President of the United States, I don’t bluff.”

One year later, Iran has yet to call it. Even as Obama has committed to using military force to prevent Iran from getting a nuclear weapon, he has worked hard to avoid war. Attacking Iran’s nuclear sites could cost American military and civilian lives, set off a wave of terrorist attacks, spike oil prices and sour the U.S.’s relations with Muslims worldwide. So Obama has tried to slow or derail the Iranian program through a combination of diplomacy, sanctions and covert action. He has succeeded in pushing the timeline for war back at least 12 months…

In the mythology of the American presidency, a Commander in Chief makes tough decisions once, unreservedly, and then acts. Just as often, though, a President acts to avoid tough decisions and then works behind the scenes to steer events, persuade friends and enemies and avoid no-win choices. As the dangerous, complicated drama involving the U.S., Iran and Israel enters its final chapters, Obama will soon face the hardest decision of his presidency. This is the story of how he got here.