WASHINGTON (By Adam Nagourney and Carl Hulse, NYTimes) March 6, 2008 — Senator Hillary Rodham Clinton’s victories in the primaries on Tuesday barely dented Senator Barack Obama’s lead in delegates, but they seemed to slow the Democratic Party establishment’s move in his direction while giving her campaign time to try to turn the race in her favor.

Mrs. Clinton’s victories in Ohio, Texas and Rhode Island cut into Mr. Obama’s delegate lead by 15 delegates at most, and by as few as 5, depending on the final accounting in Texas, which was expected Thursday afternoon.

Mr. Obama now has 1,299 delegates, compared with 1,180 for Mrs. Clinton, based on a count of pledged and projected delegates prepared by The New York Times. A candidate needs 2,025 to claim the nomination, a figure that neither Mrs. Clinton nor Mr. Obama can reach without the votes of so-called superdelegates — party officials and elected Democrats who are awarded automatic seats.

Both campaigns maneuvered for advantage on Wednesday after Mrs. Clinton’s strong showing, and they prepared for the next big showdown, in Pennsylvania, where the political demographics and issues are similar to those in Ohio.

Mr. Obama said he planned to be more aggressive in going after Mrs. Clinton in response to her attacks, setting the groundwork for a tough competition that made some Democrats nervous that the party would bloody itself.

The Clinton campaign suggested it would press on with its efforts to claim delegates from Florida and Michigan, two states where she won primaries that were held in defiance of the Democratic National Committee’s approved calendar and where neither candidate campaigned actively. Mr. Obama was not on the ballot in Michigan.

Mrs. Clinton and Mr. Obama are embracing sharply different approaches as they try to capture the nomination and rally superdelegates behind them. For Mr. Obama, it is a matter of delegate math as he argues that superdelegates should support whoever has won the most elected delegates after the primary season ends in June. For Mrs. Clinton, it is trying to build momentum — and making a case that she is more electable — to persuade superdelegates to support her.

The prospect of a protracted battle at time when Republicans were coalescing around Senator John McCain of Arizona, who secured his party’s nomination on Tuesday, created unease among at least some Democrats.

“I don’t think anybody I have talked to, whether they are a Hillary supporter, agnostic or an Obama supporter, wants to see this go to the convention, given the opportunity we have to capture the White House,” said Representative John B. Larson, Democrat of Connecticut, Obama backer and member of the House leadership.

But for now at least, aides to both campaigns said, Mrs. Clinton appeared to have frozen the race in place, and slowed the flow of superdelegates into Mr. Obama’s camp. Mr. Obama’s aides had hoped that a poor showing by her on Tuesday would result in a quick move of superdelegates to him.

“Everybody is sort of taking a deep breath right now,” said Senator Edward M. Kennedy, Democrat of Massachusetts and an Obama supporter.

In a sign of difficult times ahead, there was more pressure on the Democratic Party to devise a way to seat delegations from Michigan and Florida. The governors of both states — Charlie Crist of Florida, a Republican, and Jennifer M. Granholm of Michigan, a Democrat, issued an unusual joint statement urging the Democratic National Committee to find a solution for seating the delegations.

“It is intolerable that the national political parties have denied the citizens of Michigan and Florida their votes and voices at their respective national conventions,” Mr. Crist and Ms. Granholm said.

Howard Dean, the chairman of the Democratic National Committee, responded by suggesting that the party was open to a solution that would seat the states’ delegations provided they agreed to “follow the rules.”

In Washington, members of the Michigan and Florida Congressional delegations were meeting Wednesday night to discuss ways to resolve the impasse. Democratic Party officials in Michigan have been considering holding a caucus-style election, and a spokeswoman for Ms. Granholm said she was open to the idea as long as no public money was used. Such a caucus has also been discussed for Florida.

In this uncertain atmosphere, several Democrats said they were looking to party leaders to prevent a divisive fight that could last through the summer. But other Democratic leaders argued that the party should let the remaining contests play out.

“I think that the electoral process has to work its way,” Speaker Nancy Pelosi said. “There are still many voters unheard from.”

Mr. Obama’s supporters have argued that the superdelegates should rally around the leader in delegates at the end of the voting. They predicted that Mr. Obama would make up the delegates he lost on Tuesday with coming contests in Mississippi, with a heavily black electorate, and Wyoming, which has caucuses, a process that draws more committed voters, who have tended to support Mr. Obama.

Beyond that, the campaigns offered a taste of what was ahead. Mrs. Clinton’s aides said the results in Ohio and Texas showed that voters had concern about Mr. Obama’s credentials as commander in chief — and that would be a major problem if he ended up facing Mr. McCain.

“Let me state it categorically: This party is not going to nominate somebody who hasn’t passed the commander-in-chief test,” said Howard Wolfson, Mrs. Clinton’s communications director. “If he can’t convince Democrats in Ohio and Texas that he can be commander in chief, he is not going to be nominee of our party.”

Mr. Obama’s senior adviser, David Axelrod, pointed to Mrs. Clinton’s vote in favor of the Iraq war as evidence that she had failed the same test. “The fact remains, on the single biggest issue she’s ever had to deal with, she made a dramatically bad decision,” Mr. Axelrod said. Exchanges like this fed concern among some Democrats that the party had taken a wrong turn on the road to the general election. But other Democrats said that such a debate would in fact benefit the party, keeping Democrats in the spotlight, energizing voters and giving the ultimate nominee a testing that would come in handy.

Senator Joseph R. Biden Jr. of Delaware, who left the Democratic presidential race after losing in Iowa, said he was not worried about the consequences of the primary fight.

“I think people are getting a little too excited about it,” Mr. Biden said, suggesting that the emphasis on the Democratic contest may make it hard for Mr. McCain to be heard in the coming weeks. “I think the party is absolutely, positively united in its desire to win the White House. I don’t think there will be any problem getting back together.”

Representative Steny H. Hoyer, Democrat of Maryland and the majority leader, said, “The sooner obviously this is resolved, it may be the better.”

“On the other hand,” Mr. Hoyer added, ”it is going to be a great deal of attention paid to Mr. Obama and Mrs. Clinton over the next few weeks as well.”