Democratic Party
Candidates featured in major polls: Barack Obama
Withdrew during primaries: Hillary Clinton | John Edwards | Bill Richardson | Dennis Kucinich | Joe Biden | Mike Gravel | Christopher Dodd
Withdrew before primaries: Evan Bayh | Tom Vilsack
Republican Party
Candidates featured in major polls: John McCain
Withdrew during primaries: Mitt Romney | Mike Huckabee | Ron Paul | Rudy Giuliani | Fred Thompson | Alan Keyes | Duncan Hunter
Withdrew before primaries: Tom Tancredo | Sam Brownback | Jim Gilmore | Tommy Thompson
Other third parties:
Candidates featured in major polls: Bob Barr (Libertarian Party) | Cynthia McKinney (Green Party) | Chuck Baldwin (Constitution Party) | Ralph Nader (Independent)
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