Former Virginia Governor Mark Warner surprised fellow Democrats Thursday by announcing he will not run for president in 2008.  Many Democrats considered Warner a viable alternative to Senator Hillary Clinton of New York, who is widely seen as the front-runner for the party's presidential nomination two years from now. 

Mark Warner at a news conference in Richmond, Virginia , Oct. 12, 2006

In a written statement, Mark Warner said his decision was not based on politics, but on what was best for his wife and three daughters.

Warner said that, while it seemed the right time to take the plunge politically, he wanted a real life, and did not wish to put his family through the rigors of a presidential campaign.

The announcement stunned Democrats, especially those who considered the popular former Virginia governor a moderate alternative to Hillary Clinton in 2008.

Warner has been out campaigning for Democratic candidates in recent weeks, and testing the waters for a presidential bid.

He recently spoke at a political picnic in the early contest state of New Hampshire.

"The most distinctive American value in my mind is that everybody ought to get a fair shot.  We cannot guarantee you success, but you ought to get a fair shot, and our society ought to provide you the tools to make sure you get that fair shot," he said.

Independent political analyst Stuart Rothenberg says Warner's decision not to run for the White House in 2008 is bound to disappoint some Democrats.

"It takes away the Democrat who was seeming to emerge as the alternative to Senator Clinton, the more moderate Democrat with broader appeal," he said. "Senator Clinton now does not know as much as she and her strategists did about where the challenge to her is going to come from."

Sen. John McCain

Senator Clinton leads other Democrats in most public opinion polls as the top choice to run for president in 2008.  But some party activists and analysts question whether she can win a contest against a Republican like Senator John McCain of Arizona, widely seen as a top contender for the Republican Party presidential nomination.

Clinton has said she will decide on a presidential run after the congressional elections in November.

"For the Democrats, it is a tragedy.  He was the premier centristm" said Larry Sabato, who directs the Center for Politics at the University of Virginia. "He could have won a general election, whereas many of the Democratic candidates are too far left to win a general election."

Several other Democrats are considering a White House bid in two years, and the Warner decision to forego the race could encourage them to enter the race.

Sen. John Kerry (file photo)

Among those possibly interested in a White House run are Senator John Kerry, the party's 2004 nominee and his vice presidential running mate, former North Carolina Senator John Edwards.

Others on that list include Senators Evan Bayh of Indiana, Joe Biden of Delaware, Christopher Dodd of Connecticut and Russ Feingold of Wisconsin.

Some Democrats also mention Iowa Governor Tom Vilsack and New Mexico Governor Bill Richardson, a former U.N. ambassador, as possibilities, as well as former Vice President Al Gore, who narrowly lost the presidency in 2000 to George Bush.  Gore says he has no plans to run in 2008.