John Kerry's (search) string of wins is leading party leaders and seasoned advisers to look for ways to bring the primary season to a quick close.

"I think it is obvious from the results of these primaries as to what the handwriting on the wall is," said Leon Panetta, who served 16 years in Congress before his tenure as budget director and chief of staff in the Clinton White House.

"At some point, perhaps sooner rather than later, I think Democrats need to unify behind John Kerry and refocus on winning in November," said Panetta, who is not affiliated with any candidate.

Kerry's wins in Tuesday's primaries in Virginia and Tennessee showed his strength in the South as well as in other parts of the country and put heavy pressure on the two southerners -- Sen. John Edwards (search) of North Carolina and retired Gen. Wesley Clark (search) of Arkansas -- to bow out.

Both have portrayed themselves as the only ones who can beat President Bush in what Edwards calls his "backyard."

Democratic party officials devised this year's compressed primary schedule to avoid a protracted, money-draining nomination fight. With Kerry's surge, Democratic leaders said the process was working pretty much as intended.

But they also hope to see the field now narrow significantly so the real contest -- the one against President Bush -- can begin.

"My hope is that the winnowing process begins right after tonight," said New Mexico's Democratic governor, Bill Richardson.

Richardson said the primary season so far "has been a blessing" for Democrats, raising Americans' interest in the Democratic contests and allowing the candidates' unobstructed -- and until recently unanswered -- shots at Bush.

But enough is enough, many Democratic activists are suggesting.

Kerry, asked whether he saw his southern successes as a message to Democrats, told The Associated Press: "That's not for me to determine at all. I'm on to Wisconsin, and I think the campaign moves forward and I'm going to continue to fight for every vote."

And does it send a message to Bush? "I think it would be a presumptuous for me to try to make that determination...You take it one step at a time."

Democratic National Committee Chairman Terry McAuliffe earlier this year said any candidate who had not won a primary or caucus by February 3 -- a week ago -- should consider dropping out.

Rep. Dick Gephardt of Missouri, Sen. Joe Lieberman of Connecticut and former Ambassador Carol Moseley Braun complied.

But former Vermont Gov. Howard Dean, once considered the front-runner, Ohio Rep. Dennis Kucinich and Al Sharpton have remained in the contest despite being winless -- and have indicated that they intend to push on regardless of how well they do in upcoming primaries.

Edwards and Clark have each won one primary -- Edwards in South Carolina, Clark in Oklahoma.

A prolonged nomination fight could pose problems for the party in positioning itself to begin battling Bush, who has raised close to $150 million to spend before the GOP convention in September and was headed toward a total of $170 million to $200 million.

The cost of campaigning now is depleting the resources of the candidate who will be the nominee, presumably Kerry. Furthermore, history shows that bitter primary struggles often lead to November defeats.

"We can't be having a primary fight going on all the way through the spring," McAuliffe said.

Some Democratic strategists suggest the time is ripe to rally behind a single candidate, with polls showing the president's support is slipping and some surveys put Kerry ahead of him in a general election matchup.

There is also a risk that if the contest turns more personal, that could provide more ammunition for Republicans in the fall to use against Kerry.

"I think the establishment will try to put the screws on the less successful candidates," said Paul Begala, a Democratic consultant and TV commentator. "I don't think that's bad for John Kerry. Nothing succeeds like success."

Doug Schoen, Bill Clinton's former pollster and an unaffiliated Democratic strategist, said that prolonging the primary battle could theoretically work against Democrats in the fall. But, in practical terms, he said, "Kerry is getting such support across all demographic groups, I don't see Dean or Clark or Edwards as posing a serious threat to Democratic unity."

He predicted that Kerry would wind up "with more than 90 percent of all Democrats supporting him" and would have the nomination locked up well before March 7, the day Al Gore passed that milepost in 2000.

One senior Democratic party official, speaking on the condition of anonymity, suggested that party leaders would let the race play out at least until next week's Wisconsin primary before coming down hard on laggards.

Joe Lockhart, a Democratic consultant who was Clinton's press secretary, said he senses both a desire to wrap things up and "an appetite within the party and the press to see a one-on-one matchup with the front-runner."

"I think it's good for the party, good for Kerry, to keep this race competitive for just a little longer," Lockhart said.