WASHINGTON (CNN) -- Sen. John McCain said Tuesday that President Bush's new strategy in Iraq is "succeeding as we speak," and he believes the American people can be persuaded to support continuing a U.S. military presence in Iraq if they can be shown a "path to success."

"I am confident in a short time we've already achieved some measurable successes," McCain said on CNN's "The Situation Room," citing improved security in some Baghdad neighborhoods and better cooperation from tribal leaders in Anbar province. "That doesn't mean it isn't going to be hard and tough." (Watch video: CNN's Wolf Blitzer interviews Sen. McCain)

The Arizona Republican, who is seeking his party's 2008 presidential nomination, said he believes that a year from now, the situation in Iraq will either be much better or much worse, and, if the latter situation comes to pass, "then obviously we're going to have to examine a set of bad options."

"But I'm confident it won't be (worse)," McCain said. "If I'm wrong, we've got a lot more problems than anything it does to my political reputation."

McCain has been an outspoken supporter of Bush's plan to boost troop levels in Baghdad and Anbar province as part of a new strategy designed to quell terrorist attacks and sectarian violence.

Asked why he thinks a majority of Americans now tell pollsters they would support a troop pullout by next fall, McCain said it is "because the American public is frustrated and angry and saddened by our failure and mismanagement of the war." But he also said he believes public support can be rebuilt if the situation in Iraq improves -- and that failure would be a "catastrophe."

"Failure is genocide. Failure means we come back. Failure means they follow us home," McCain said.

McCain also said, "There is no doubt that we may require troops there for a long period of time," likening the situation to Korean peninsula, where the United States maintains a military presence more than 50 years after the end of the Korean War.