Obama vs. Clinton vs. Kerry in '08?

Today's debate between Hillary Clinton and her Republican challenger was supposed to be about the midterm elections, two weeks away.

But the opening question was about the election two years away. Clinton refused to renew her pledge of six years ago to serve a full term in the Senate, leaving the door open to a presidential bid in 2008.

"I can't make a decision now, I have made no decision," she said. "But if that concerns any voter, they should factor that into the vote they make."

The more surprising declaration of the day came from the Democratic party's rising young star.

Freshman Illinois Sen. Barak Obama has graced magazine covers including Time, Newsweek and Men's Vogue.

His comments to NBC's Tim Russert on "Meet the Press" are sure to keep him in the media spotlight for some time to come. Asked whether it's fair to say he's thinking about running for president in 2008, Obama said, "It's fair, yeah."

When Russert continued, "So it sounds as if the door has opened a bit," Obama admitted, "A bit."

Kerry Might Throw His Hat Into the Ring

John Kerry is thinking about a second White House run. He may lack Obama's flash, but on ABC News' "This Week with George Stephanopoulos," he said he welcomes the competition.

"If he thinks he's ready to run for president and wants to run, and I've made a decision … then we'll go out and have a great contest," Kerry said.

With or without Kerry as a contender, an Obama candidacy could be a powerful force.

"A lot of other candidates are going to be pushed to the side in media attention, money and political support if you have two titans -- Hillary Clinton and Barak Obama -- running for president," said Mark Halperin, ABC News political director and co-author of "The Way to Win: Taking the White House in 2008."

The road to the White House begins in the early caucus and primary states -- Iowa and New Hampshire. Obama made his first visit to Iowa last month. Hillary Clinton hasn't made the trip, but another politician named Clinton has -- her husband, former President Bill Clinton.

Democrats aren't the only ones heading to the state. Republican Mitt Romney, governor of Massachusetts, has been to Iowa nine times as he chases the early GOP front-runner, Arizona Sen. John McCain.

"Mitt Romney is going around the country," Halperin said, "and implicitly saying if you have doubts about John McCain … if you're looking for another horse to bet on not named McCain, I'm your guy, and he's having some success."

A Clinton-Obama race would pit a former first lady and veteran of the public scene against a newcomer who's publicity has been virtually all positive. But even Obama himself admits, that's something that would change the minute he became a candidate.