WARREN: What’s the most significant — let me ask it this way. What’s the most gut-wrenching decision you ever had to make and how did you process that to come to that decision?

OBAMA: Well, you know, I think the opposition to the war in Iraq was as tough a decision as I’ve had to make. Not only because there were political consequences, but also because Saddam Hussein was a real bad person, and there was no doubt that he meant America ill. But I was firmly convinced at the time that we did not have strong evidence of weapons of mass destruction, and there were a lot of questions that, as I spoke to experts, kept on coming up. Do we know how the Shia and the Sunni and the Kurds are going to get along in a post-Saddam situation? What’s our assessment as to how this will affect the battle against terrorists like al Qaeda? Have we finished the job in Afghanistan?

So I agonized over that. And I think that questions of war and peace generally are so profound. You know, when you meet the troops, they’re 19, 20, 21-year-old kids, and you’re putting them into harm’s way. There is a solemn obligation that you do everything you can to get that decision right. And now, as the war went forward, there are difficult decisions about how long do you keep on funding the war, if you strongly believe that it’s not in America’s national interest. At the same time, you don’t want to have troops who are out there without the equipment they need.

So all those questions surrounding the war have been very difficult for me.