"Simply put, it's the Obama factor," said Democratic pollster Peter Hart. "Obama's entry into the presidential race essentially raised the ante. Candidates who used to do careful exploration with the hope that they could catch fire in Iowa and New Hampshire and move from there recognize that there's no oxygen left out there for their candidacies."
Republicans have their own celebrity candidates in Arizona Sen. John McCain and former New York Mayor Rudolph Giuliani, but they cast a far smaller shadow on their rivals. Those so far sidelined in the GOP race - Sens. Bill Frist of Tennesee and George Allen of Virginia - have landed there through their own mistakes, not the looming presence of the two early poll leaders.
Dominating candidates are not new to presidential campaigns, nor is it uncommon for some politicians to explore a candidacy but never run. In 1992, many prominent Democrats chose not to run, fearful that President George Bush could not be defeated.
Even though neither has announced for president, Clinton and Obama have demonstrated the advantages of celebrity status in a world of cable news and expanding Internet communities. They have the capacity to raise tens of millions of dollars with relative ease.
Only former Vice President Al Gore might be able to command the kind of attention Clinton and Obama receive, say veteran strategists. But he has made no serious moves toward running.
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