WHITE MARSH, Md. — Senator Clinton denied today that her campaign is in trouble after losing to Senator Obama in four states this past weekend and replacing her campaign manager.

“I’m still ahead in the popular vote and in delegates,” Mrs. Clinton said.

Speaking to reporters after touring a General Motors plant outside Baltimore, Mrs. Clinton said she feels very good about the state of the race, even though she is not expected to win between now and March 4, when voters in Texas and Ohio cast ballots.

“We had a great night on Super Tuesday,” Mrs. Clinton said, referring to the 22 states that voted February 5. Mrs. Clinton won eight states to Mr. Obama’s 13 but scored in many of the biggest contests including New York, California, Massachusetts, and New Jersey. And they divided the delegates almost evenly.

“I believe if you look at the states … upcoming, I am very confident.”

The former first lady said the decision by Patti Solis Doyle to step down as campaign manager was personal and reflected the toll of the long campaign, not a problem with her job performance.

“I have the greatest respect and affection for her,” Mrs. Clinton said. “I’m grateful for the enormously successful job that she’s done.”

She said Ms. Solis Doyle would remain a senior adviser. A longtime Clinton confidante and former chief of staff from Mrs. Clinton’s days as first lady, Maggie Williams, replaced Ms. Solis Doyle.

Ms. Solis Doyle’s departure capped a rough weekend for Mrs. Clinton after she lost the Louisiana primary and caucuses in Nebraska, Washington state, Maine, and the Virgin Islands to Mr. Obama.

She said she never expected to do well in any of those contests, even though she had been favored to win Maine. Mrs. Clinton repeated her criticism that the caucus system is undemocratic and caters mostly to party activists.

As for Louisiana, “You had a very strong and very proud African-American electorate, which I totally respect and understand,” Mrs. Clinton said.

She noted that the states she won on Super Tuesday were all states Democrats must win to succeed in the general election. Many of the states Mr. Obama won that night, such as Alaska and North Dakota, would not be competitive for Democrats next November, she said.

The New York senator also dismissed concern that Mr. Obama had all the momentum going into the next round of contests. He’s expected to sweep the so-called Potomac primary tomorrow, when Maryland, Virginia, and the District of Columbia cast votes, and is favored next week in Wisconsin and Hawaii.

“Before Super Tuesday you all were reporting on all the momentum. It didn’t turn out to be true,” she said. “Let’s have the elections. Instead of talking about them, pontificating and punditing, let’s let people actually vote.”

Earlier today, Mrs. Clinton addressed a campaign audience in the District of Columbia.

She told a small gathering sponsored by the National Council for Negro Women that she supports full voting rights for District residents.

“I think this is long overdue,” Mrs. Clinton said to cheers. “I think it is wrong that we disenfranchise the people who live and work in this city.”

Voting rights in a significant issue in Washington, where nearly 60% of the population is black. The former first lady has struggled to gain traction with black voters in her race against Mr. Obama, who hopes to be the first black president.