When John Kerry (search) selected Senate colleague John Edwards (search) as his running mate, he created a likely front-runner for the Democratic presidential nomination in 2008 — and a reshuffling of expectations for others — should President Bush win a second term in November.

Sen. Hillary Rodham Clinton (search), D-N.Y., has long been considered a top contender in 2008 if Kerry's bid falters. The former first lady's star power, though, could be challenged by Edwards if an intense, four-month campaign raises his profile, he's a serious player," said Chicago media consultant David Axelrod, who advised Edwards during his nomination campaign. "He has elevated himself at every part of the process."

A victory by Kerry in 2004 could set up an Edwards campaign for the White House in 2012 even if the pair were to lose re-election in 2008. Yet others with aspirations will be part of the scramble in four years if there is no Democratic president to consider for another term.

"Hillary is the giant in the corner," said Democratic consultant Dane Strother.

Clinton avoids discussing her place in presidential politics, but no other potential candidate raises as many expectations in both parties — from the Democrats who cheer her to the Republicans who love to hate her.

"Senator Clinton is always going to be a star," said Iowa Gov. Tom Vilsack, who was on the short list of potential Kerry running mates before Edwards was tapped.

After weeks of speculation that he might be Kerry's pick, the two-term governor is a more recognizable face in the Democratic crowd. "There is no doubt that Tom Vilsack's future is very bright in the Democratic Party," said Sen. Tom Harkin, D-Iowa, who had urged Vilsack for the ticket.

Another Democrat considered by Kerry, New Mexico Gov. Bill Richardson, remains a popular figure with appeal to fellow Hispanics and certainly would be part of the mix in 2008, Strother said.

Forty-something candidates in the Kerry veepstakes could be eyeing the top of the Democratic ticket in four years, including Sen. Evan Bayh of Indiana and Virginia Gov. Mark Warner. On the sunny side of 60 are political veterans such as Sens. Joe Biden of Delaware and Bill Nelson of Florida, and Pennsylvania Gov. Ed Rendell.

All must wait and see how Edwards performs on the national stage.

"He'll no longer be seen as green. He'll be much more seasoned," said pollster Lee Miringoff, head of Marist College's Institute for Public Opinion. "If someone else had been picked and Bush was re-elected, the first question from the media would have been to Hillary Clinton. Now there are two microphones to be used."

Running mates are traditionally relegated to the sidelines during the fall campaign, yet there will be a few defining moments that will go a long way toward shaping Edwards' future. One coming late in the race is his debate Oct. 5 in Cleveland with Vice President Dick Cheney.

Running mates have often sought the presidency in later elections. Even those on a losing ticket can have a shot: Franklin D. Roosevelt was James Cox's running mate when they lost the 1920 election but returned to presidential politics as the Democratic nominee in 1932. Bob Dole lost the 1976 race with Gerald Ford but was the GOP's nominee in 1996, with Jack Kemp as his running mate.

"Just ask Jack Kemp what it did for him when Ronald Reagan picked George Bush for vice president" in 1988, said Nelson Warfield, a veteran Republican operative.

Simply joining the ticket doesn't ensure a nomination for president down the road. Former Vice President Dan Quayle could never interest enough Republicans in his candidacy. Sen. Joe Lieberman, the Connecticut Democrat who ran with Al Gore in 2000, dropped out of the presidential race this year after he failed to gain support.