WASHINGTON -- This week's first presidential debate of the 2008 general election will pit a homely "straight talker" against the most gifted orator of his generation.
In truth, however, Republican John McCain has long since ditched the freewheeling style of communication that was his trademark to stay rigorously on message as the White House campaign has heated up.
And Democrat Barack Obama, in debate settings, trades his barnstorming speechifying for a more nuanced and professorial approach.
But both candidates showed during the primary campaign that they are capable of rhetorical zingers. And, given the high stakes at play, there is every possibility of fireworks when they clash at Friday's debate.
McCain's Republican rival Mitt Romney got a tongue-lashing from the Vietnam war veteran over the former Massachusetts governor's serial shifts in belief down the years.
At a New Hampshire debate in January, Romney boasted of his business acumen as a former venture capitalist. McCain fired back: "I led the largest squadron in the US Navy, not for profit but for patriotism."
While he struggles in front of a teleprompter, in contrast to the eloquent Obama, McCain has flourished in unscripted debates and "town hall" meetings with voters.
Perhaps the Arizona senator's best-remembered moment of the primary debates came with an attack on Obama's own party rival, Hillary Clinton.
Last October, he earned a standing ovation for a caustic dig at the New York senator's request for federal funding to build a museum to commemorate the 1969 music festival at Woodstock.
"I wasn't there. I'm sure it was a cultural and pharmaceutical event. I was tied up at the time," the former prisoner of war said drily.
Obama meanwhile showed against Clinton that there was a steel lining to his mantra of hope. Their simmering feud spilled over into outright hostility at a debate in South Carolina in January.
The Illinois senator told Clinton that "while I was working on those (Chicago) streets watching those folks see their jobs shift overseas, you were a corporate lawyer sitting on the board at Wal-Mart."
And at a February debate in Ohio, Obama rebuffed an angry complaint from Clinton as their contest for the Democratic nomination turned ever more nasty.
Clinton's campaign had "sent out negative attacks on us, e-mail, robocalls, flyers, television ads, radio calls. And, you know, we haven't whined about it because I understand that's the nature of these campaigns," he said.
So which Obama will show up for Friday's prime-time debate at the University of Mississippi in Oxford - the hope-monger or the Chicago-bred street-fighter?
And which McCain will be on display - the self-deprecating straight talker who was once a darling of the media, or the disciplined operative now running a campaign accused by many in the press of resorting to lies?
In fact, both sides of the candidates are certain to come out if, like previous presidential debates, the event's tenor alternates between convivial and combative.
© 2008 Agence France Presse. All rights reserved.