He quickly backed off that remark.
"Let me not put it that stark," the likely GOP nominee told reporters on his campaign bus. "Let me just put it this way: Americans will judge my candidacy first and foremost on how they believe I can lead the country both from our economy and for national security. Obviously, Iraq will play a role in their judgment of my ability to handle national security."
"If I may, I'd like to retract 'I'll lose.' But I don't think there's any doubt that how they judge Iraq will have a direct relation to their judgment of me, my support of the surge," McCain added. "Clearly, I am tied to it to a large degree."
The five-year-old Iraq conflict already is emerging as a fault line in the general election, with the Arizona senator calling for the U.S. military to continue its mission while his Democratic opponents urge speedy withdrawal.
While most Republicans still back the war, many independents and Democrats don't. That presents a significant challenge for McCain and an opportunity for either Barack Obama or Hillary Rodham Clinton.
McCain acknowledged the war will be "a significant factor in how the American people judge my candidacy."
The lead Republican on the Senate Armed Services Committee, McCain has consistently backed the war although he's long criticized the way it was waged after the Saddam Hussein's fall. He was an original proponent of President Bush's troop-increase strategy, having called for more forces on the ground for several years. Last spring, McCain went all in on the war by embracing it as Bush took heat for boosting troop levels to quell violence.
"We can fail in Iraq," McCain said Monday in an Associated Press interview. But, he added: "I see a clear path to success in Iraq." He defined that as fewer casualties and Iraqi troops taking over security to allow U.S. forces to return home. "All of us want out of Iraq, the question is how do we want out of Iraq," he added.
McCain has signaled that he plans to make Iraq and national security a major part of his general election campaign. Daily, he accuses both Obama and Clinton as wanting to "wave the white flag of surrender." Democrats, for their part, are arguing that McCain's candidacy is simply a continuation of Bush's "failed" policies. They have seized on a previous McCain remark in which he suggested that U.S. troop presence - at some level - could extend 100 years or more.
At a town hall-style meeting in suburban Cleveland, McCain accused Democrats of distorting that comment and sought to explain.
"The war will be over soon, the war for all intents and purposes, although the insurgency will go on for years and years and years.
But it will be handled by the Iraqis, not by us," he said. Like after other wars, he said, the United States then will decide "what kind of security arrangement we want to have with the Iraqis."
While McCain attracts voters across the political spectrum, he is sure to face resistance this fall for his Iraq position in Ohio and other swing states that have seen high numbers of residents die in Iraq.
Over the next eight months, McCain said he would take the same approach when discussing Iraq that he's taken all year as he won primary after primary on his way to securing the GOP nomination.
Speaking to reporters on his bus, he said he would "tell them that I understand their frustration and their sorrow over the sacrifice that has been made and then I try to explain to them what's at stake and what's going on there now. And that's the best I can do."
McCain said his candidacy will be successful "if I can convince the American people, the people of Ohio, that this is succeeding, that the casualties will continue down, although there are occasional spikes."
"So I have to, and I believe can, make an argument that the surge is succeeding, that we will end this war and have the Iraqis take over those responsibilities as we more and more assume support roles and then withdraw," he added.
McCain recalled reading a USA Today poll that he said showed most people believe the troop-increase strategy is succeeding, and said: "Now, still the majority of Americans want out of Iraq. And, I understand that, too. So do I."
The survey actually found that 43 percent - not a majority - said the troop increase is "making the situation there better," up from 22 percent in July.
Asked why he asked to retract the "I lose" remark, McCain said much else could impact his chances.
"We've got many months to go before the general election," he said. "But is Iraq an important part of the judgment that people will make of me, of course."
