Maintaining the momentum of this weekend's four wins in Washington State, Nebraska, Louisiana, and Maine, Sen. Barack Obama visited the University of Maryland a day before the "Potomac primary" to stir up young supporters and take on both his rivals—Sens. Hillary Clinton and John McCain.

As the audience of about 17,000 at the University of Maryland echoed, the senator from Illinois was "fired up" and "ready to go," telling supporters that Clinton's claim that they should vote for her because she is tough and able to fight off Republicans wasn't unique to her.

"Well, let me tell you something: I'm skinny, but I'm tough, too. I'm looking forward to mixing it up with John McCain," Obama said the day before voters in Virginia, Maryland, and Washington, D.C., would have a chance to vote in the presidential primary.

But first, Obama has Clinton to contend with.

The two Democrats continue to be neck and neck in the delegate race nationally. Obama has gotten help in the Potomac region by having Virginia Gov. Tim Kaine and Washington Mayor Adrian Fenty on his side. Clinton has had support from Maryland Gov. Martin O'Malley. While Obama is ahead in the polls in the Potomac primary and expected to handily win the popular vote in all three jurisdictions, the trifecta of campaigning Clintons has been out and about in the region, too, even while the Clinton campaign is more heavily focusing on the delegate-rich primaries in Texas and Ohio on March 4.

Chelsea Clinton visited the University of Maryland Sunday to chat with 250 students in the Stamp Student Union, while her mother spoke to more than 1,000 supporters down the road at Bowie State University. Former President Bill Clinton asked the forgiveness of the congregation of one of Washington's largest black churches Sunday for racially tinged comments he made in South Carolina concerning Obama. On Monday, Senator Clinton toured the General Motors Baltimore Allison Transmission plant and then headed to the University of Virginia.

But Obama's popularity among young people showed when he drew in Monday's massive crowd in Maryland. The Comcast Center, where the Maryland Terrapins basketball team plays, was filled almost to the brim with people of all ages hoping to get a peek at the senator. Maryland students waited in the bitter cold in a line that was easily several miles long, some staying up all night in anticipation of the visit. High schoolers poured out of the College Park metro station and stuffed themselves into the University of Maryland's red buses to reach the event. Students held "Barack My World" and "Party Like Barack Star" signs, among others, and treated Obama, well, like a rock star.

He addressed the concerns of some that he is a "hope-monger."

"There are some folks who say, 'He hasn't been in Washington long enough...we have to season and stew him a little longer—boil all the hope out of him,'" Obama said. "I notice this argument hasn't worked with the American people because they understand that the last thing we need is to have the same old cast of characters doing the same old thing."

Obama talked about getting every American on board and even spoke of Republicans who support him, a new breed of political enthusiasts called "Obama-cans."

"Hey Barack—I'm a Republican," shouted a middle-aged bearded man from the audience, donning a camouflage cowboy hat. Point noted.