McLEAN, Va. — Democrat Hillary Rodham Clinton replaced her campaign manager yesterday as rival Barack Obama rode momentum from five weekend victories into primaries tomorrow in Maryland, Virginia and the District of Columbia.

In the largely settled Republican race, President Bush sought to rally the party behind likely nominee John McCain. The Arizona senator won a weekend contest in Washington state. But in a sign of continuing resistance from religious and other conservatives, former Arkansas Gov. Mike Huckabee — a Baptist minister — won Louisiana and Kansas.

"He is a true conservative," Bush said of McCain, his rival in the 2000 primaries, on "Fox News Sunday."

Obama, an Illinois senator, won the Maine caucuses yesterday after victories Saturday in Louisiana, Nebraska, Washington and the Virgin Islands. On top of that, he beat out two former presidents — Bill Clinton and Jimmy Carter — to win a Grammy for his reading of his book, "The Audacity of Hope."

POTOMAC PRIMARY

With 99 percent of the vote counted in Maine, Obama held 59 percent of the vote, to 40 percent for Clinton.

Clinton's new campaign manager, Maggie Williams, was her chief of staff in the White House. The departing official, Patti Solis Doyle, said she would be a senior adviser.

The campaign did not explain the move. "The statement speaks for itself," spokesman Phil Singer said.

All three jurisdictions in tomorrow's Potomac primary are led by Democrats: Virginia Gov. Tim Kaine for Obama, Maryland Gov. Martin O'Malley for Clinton and D.C. Mayor Adrian Fenty for Obama.

Kaine said Obama is the underdog though he has raised more money and won more states. "The Clinton political operation is the best Democratic political operation in the last 40 years," he said.

O'Malley said Maryland Democrats have a "tremendous amount of respect for the kind of progress that was made during President Clinton's administration" and that will benefit the former first lady.

OBAMA FAVORED

The "Potomac primary" is an effort by local leaders to gain clout by banding together. At stake are 168 delegates for Democratic candidates and 119 for Republicans.

Obama has battled Clinton to a draw on delegates in contests to date. According to The Associated Press' latest tally, Clinton has a total of 1,136 delegates and Obama has 1,108, following his victory in Maine's caucuses. That includes super delegates — party leaders who are free to support whomever they want. A candidate must get 2,025 delegates to capture the nomination.

Clinton made an unannounced trip to Chapel Hill, N.C., last week to seek an endorsement from former Sen. John Edwards, who gave up his presidential bid last month. Obama is scheduled to meet with Edwards on a similar mission early this week, a source close to Edwards told the Chicago Tribune.

Obama Communications Director Robert Gibbs declined to comment.

Demographics favor Obama tomorrow. All three Potomac primary jurisdictions are bastions of black voters and highly educated voters, two groups he has carried by large margins in earlier contests.

Clinton has shown strength among working-class voters, who will play bigger roles in later contests in Ohio, Texas and Pennsylvania.

HUCKABEE FIGHTS ON

Virginia's conservative Christians are a natural Huckabee constituency and they could cast "a protest vote" tomorrow, said Robert Lang, co-director of Virginia Tech's Metropolitan Institute. But he said Virginia also has many secular Republicans and military retirees, two groups likely to propel McCain to a victory.

McCain, well ahead in the voting so far, stayed off the campaign trail yesterday.

Huckabee was undeterred. "In politics," he said yesterday on CBS' "Face The Nation," "so many things can happen that can change the landscape overnight."

"To step aside and have a coronation instead of a nomination, that's the antithesis of everything Republicans stand for," Huckabee said on NBC News' "Meet the Press."

"Miracles are still happening," the ordained Baptist minister said. "I still believe in them."

Rep. Ron Paul of Texas issued a statement on his Web site vowing to "fight on, in every caucus and primary remaining" while acknowledging that he would have to devote time to his re-election bid for his congressional seat.

The Associated Press, Chicago Tribune and Washington Post contributed to this report.