Mark J. Terrill, Associated Press
Sen. John McCain adjusts his collar as Texas Rep. Ron Paul, left, responds to a question at a Republican debate in Simi Valley, Calif., Jan. 30.

WASHINGTON — The coming debates are John McCain's high wire act.

For better and for worse, he's been at these altitudes before.

In debates during his current presidential run and in his ill-fated 2000 campaign, McCain managed to disarm crowds with humor, embrace questioners with empathy or slice his foes with undisguised contempt.

Few who watched his debate last October in Orlando, Fla., will forget how the former Vietnam prisoner of war scoffed at federal funds for a museum to remember the 1969 Woodstock music festival. With impeccable comic timing, McCain said: "I wasn't there. I'm sure it was a cultural and pharmaceutical event. I was tied up at the time."

Or how he rose from his seat in New Hampshire and solemnly responded to a woman whose brother had been killed in Iraq.

"He understands the power of the moment," said Alan Schroeder, a Northeastern University professor and author of "Presidential Debates: Fifty Years of High-Risk TV." "He seems to be aware of how to take advantage of it."

Naturally combative, however, McCain also can be peevish and short-tempered when he engages a rival one on one.

"When he debates people whom he holds in high regard, he's very respectful and very even-handed and therefore very effective," said Dan Schnur, who advised McCain's 2000 presidential campaign and is now director of the Jesse Unruh Institute of Politics at the University of Southern California. "But he tends to lose his patience with people he doesn't think as highly of. As long as he doesn't let (Democrat Barack) Obama get under his skin, he'll be fine."

As Schroeder put it: "A lot of what happens in debates is not just what you do, but it's how you treat your opponents."

At the height of the Republican primaries, McCain could barely contain his disdain for former Massachusetts Gov. Mitt Romney. In a Jan. 30, 2008, debate in Simi Valley, Calif., McCain struck a dismissive tone with his rival and slipped in a dig at Romney's background as a venture capitalist when he was asked whether Romney was ready to be a military commander.

"Oh, I'm sure that, as I say, he's a fine man," McCain said. "And I think he managed companies, and he bought, and he sold, and sometimes people lost their jobs. That's the nature of that business."

In 2000, he famously flared up at then-Gov. George W. Bush during a Columbia, S.C., debate after Bush had appeared with a military veteran who accused McCain of abandoning veterans.

"You should be ashamed, you should be ashamed," McCain said as Bush attempted to interject. "You're putting out stuff that is unbelievable, George, and it's got to stop."

McCain and Bush have since reconciled, and McCain is now carefully seeking again to distance himself from the unpopular president. He has done so subtly.

In the Orlando debate, for instance, McCain said he had looked into then-Russian President Vladimir Putin's eyes only to see the letters "K-G-B." It was a pointed reply to Bush's claim that upon meeting Putin in 2001, he looked him in the eye and got "a sense of his soul."

Of the three debates scheduled this fall, McCain may feel most at home at an Oct. 7 matchup where members of the audience will ask questions.

McCain perfected his command of town hall-style events during his ill-fated 2000 presidential race. He was so confident about his abilities that he challenged Obama to a series of town hall debates this past summer; Obama declined.

"He's obviously very comfortable in a town hall kind of format," said GOP pollster Whit Ayres. "He's very good at handling questions out of left field."

Indeed, perhaps his strongest debate performance came in June 2007 in New Hampshire. His direct response to a woman whose younger brother had been killed in Iraq set the emotional high water mark for the evening.

McCain left his chair and approached the edge of the stage and in a somber, gentle voice said: "Ma'am, I want to tell you, thank you for your brother's service and sacrifice to our country."

He then went on to offer his support for a troop surge in Iraq, but not before saying: "This war was very badly mismanaged for a long time, and Americans have made great sacrifices, some of which were unnecessary because of this management of the — mismanagement of this conflict."

With that, he severed a link to Bush, upgraded his national security credentials and put the hall's crowd squarely on his side.