COLLEGE PARK, MD. - Barack Obama appeared poised Monday to trounce Hillary Clinton in today's "Potomac primary," as polls showed him with huge leads in Maryland and Virginia.

Obama, fresh from five weekend wins over Clinton in Louisiana, Washington state, Nebraska, Maine and the U.S. Virgin Islands, is hoping to add enough of the 168 delegates who are at stake in Virginia, Maryland and the District of Columbia to end the two Democrats' virtual tie. He also hopes that big wins today will enhance his campaign's momentum ahead of the showdowns March 4 in Texas and Ohio.

Clinton, who campaigned Monday at a General Motors transmission plant in suburban Baltimore, tried to project that she was strong and on the march.

"I feel good about where we are," the New York senator said, reminding her audience that "I'm still ahead in the popular vote and delegates."

However, while Clinton tried to sound upbeat, her campaign tried in advance to discount the impact of today's primaries by focusing on March 4.

Meanwhile, an enthusiastic crowd of about 17,500 greeted Obama at the University of Maryland's Comcast Center.

"It looks like we're having March madness a little early," the Illinois senator told supporters at the basketball arena. He talked about cleaning up the Chesapeake Bay, ending the Iraq war and taking on Clinton.

The audience was impressed. "Amazing. He's an inspiring figure," said Wayne Shaw, 37, a project manager for a satellite communications company.

On the Republican side, Arizona Sen. John McCain is expected today to add to his big delegate lead over former Arkansas Gov. Mike Huckabee and Texas Rep. Ron Paul.

McCain's strengths in the region are clear: Maryland and Virginia have large military and veteran populations. In Virginia, registered voters can vote in either party's primary, and polls have found that McCain's popularity among independents should help him.

McCain appeared unconcerned by his weak showing over the weekend, when he lost Louisiana and Kansas to Huckabee and barely won Washington state in a caucus whose outcome Huckabee is challenging.

"I never expected a unanimous vote, although I'd certainly like to have that. ... I have something close to 800 delegates, and last time I checked, Governor Huckabee had very few," McCain said in Annapolis, Maryland's capital. "So I think I'm pretty happy with the situation, although I recognize we have a lot of work to do."

On Monday, Huckabee reiterated his intention to stay in the race until someone gets a majority of delegates.

"Let's show them that the election isn't over until the people have spoken," he told backers at the Sheraton Richmond West Hotel.

McCAIN REJECTS MATCHING MONEY: McCain, a passionate advocate of limits on campaign finances, is turning down government matching funds for the primary season to free him to spend more money as he prepares for a general election contest.

McCain had asked to participate in the public system last summer when his campaign, his fundraising and his poll numbers hit a low point that threatened to unravel his candidacy.

Though the FEC declared him eligible for $5.8 million in December, the money would not have become available until next month. By accepting the money, moreover, McCain would have been required to limit his spending for the primaries to about $54 million -- an amount the campaign is close to reaching.

By not taking the money, McCain is free to raise more.