Democrat Mark R. Warner, the former governor of Virginia, has decided not to run for president in 2008, saying he wanted "a real life" and feared the impact of a drawn-out campaign on his family.

"This is the right time for me in my life to have a life for a little while," Warner told reporters at a downtown Richmond hotel.

The Democrat, 51, would not rule out running for the Senate or seeking the governorship again; the state bars incumbents from seeking re-election. He also left open the possibility of a future presidential bid, but conceded: "Things will probably never be as aligned as they are right now."

Warner said he arrived at his decision over several weeks. He said neither his wife, Lisa Collis, nor his daughters, ages 12, 15 and 16, discouraged him from running. In a written statement, he said he made the decision after celebrating his father's 81st birthday and taking his oldest daughter on a college tour.

"I know these moments are never going to come again," Warner said. "This weekend made clear what I'd been thinking about for many weeks — that while politically this appears to be the right time for me to take the plunge, at this point I want to have a real life.

"And while the chance may never come again, I shouldn't move forward unless I'm willing to put everything else in my life on the back burner," he said.

Since Warner left the governor's office in January, he has busily toured key states in the Democratic nomination process, including New Hampshire and Iowa. His political action committee, Alexandria-based Forward Together, has raised money for Warner's exploratory effort and for other Democratic candidates in this year's midterm elections.

"This is not a choice that was made based on whether I would win or lose," Warner said in his statement. "I can say with complete conviction that 15 months out from the first nomination contests, I feel we would have had as good a shot to be successful as any potential candidate in the field."

Warner leaves a crowded field of possible Democratic candidates.

Sen. Hillary Rodham Clinton of New York is widely considered the front-runner for the nomination. Others considering or positioning themselves for a run include Sen. John Kerry of Massachusetts, the 2004 Democratic nominee; former Sen. John Edwards of North Carolina, the vice presidential nominee two years ago; Sens. Evan Bayh of Indiana, Joe Biden of Delaware, Christopher Dodd of Connecticut, Russ Feingold of Wisconsin, Iowa Gov. Tom Vilsack and New Mexico Gov. Bill Richardson.

Warner, a centrist who had won in a Republican-leaning state, was seen as a viable Democratic alternative to Clinton. Just last week, Warner traveled to Florida, a critical battleground state, to raise money and help other Democrats. He talked about how his ability to work with Republicans could appeal to Democratic primary voters.

"We have to really get it right and getting it right will require big enough change that it can't be a Democrat-only answer or a Republican-only answer." Warner said. "I think people ... even though they are hardcore Democratic activists, get that."

During his tenure as governor, Warner's approval rating was in the mid-70s in a state that hasn't supported a Democratic presidential nominee since 1964. His lieutenant governor, Timothy M. Kaine, rode that popularity last year to replace Warner, who left because of the state's one-term limit.

Warner could be considered for a vice presidential spot. Another possibility would be Sen. John Warner's seat in 2008. The five-term senator — no relation — is 79.

Mark Warner was elected governor in 2001, defeating Republican Attorney General Mark Earley. The former state Democratic Party chairman, who made a fortune in the infancy of the cellular telephone industry, had never held elected public office.

After a difficult start with a Republican-controlled General Assembly, Warner in 2004 brokered a compromise between Democrats, moderate senators and 17 House Republicans to pass a budget-balancing $1.4 billion tax increase. The tax increase was widely regarded as the signature initiative of his four-tear term.

Warner then returned to private business.