Illinois Sen. Barack Obama took a large step towards winning the Democratic nomination for president Tuesday, capturing significant wins in the so-called Potomac Primary and making gains in key demographics that were previously strongholds for Se

n. Hillary Rodham Clinton (D).

Obama won the Virginia primary 67 percent to 36 percent, with 97 percent of precincts reporting. He also won the Maryland and Washington D.C. contests, sweeping the day.

Speaking at a campaign event in Madison, Wis. as the results came in, Obama stressed that his campaign was succeeding because voters recognize the need to change Washington. “At this moment the cynics can no longer say that our hope is false,” Obama said. “We have now won east and west, north and south and across the heartland of this country we love.”

Looking ahead to the general election, Obama targeted Arizona Sen. John McCain, the presumptive Republican nominee. Referring to previous comments, Obama said McCain believes U.S. troops could be in Iraq for 100 years. “A hundred years,” Obama repeated, “which is reason enough not to give him four years in the White House.”

Obama capitalized on the increasing energy surrounding his campaign in his wins Tuesday. Since splitting delegates with Clinton on Super Tuesday Feb. 5, Obama has won all eight contests. And with Tuesday’s results, he has unquestionably passed Clinton in the delegate count.  

“Obama is on a roll,” Larry Sabato, the Director of the Center for Politics at the University of Virginia, said. “When you win as many contests in a row as he has, it does build that intangible called momentum. February now belongs to Obama.”

A Virginia exit poll conducted by CNN showed Obama made significant inroads into Clinton’s base of supporters, drawing support from virtually every voter group. He was expected to perform well with younger voters and African Americans and he did. Sixty-seven percent of respondents under 45 voted for him and nearly 90 percent of African Americans voted for him.

But Obama also won in demographics Clinton previously owned. He beat Clinton in voters over 60 in Virginia (52 to 47) and white voters in Virginia narrowly supported him over Clinton (50 to 49). Most surprising: Virginia women backed Obama 59 to 41 over Clinton.

Several factors contributed to Obama’s win. “Even though the Clintons were in the White House for eight years, they didn’t spend a lot of time in Virginia and [President Bill Clinton] didn’t carry Virginia in either election,” Robert Holsworth, a political scientist at Virginia Commonwealth University said. “Obama spent quite a bit of time here.”  

Obama also garnered the support of important Virginia politicians, notably former Governor and Richmond Mayor Douglas Wilder (D), as well as Gov. Tim Kaine (D), Alexandria Mayor William D. Euille and former lieutenant governor Don Beyer, who lives in Alexandria and is Obama’s Mid-Atlantic finance chair.

Obama’s brand of politics meshes well with Virginia’s. “Obama’s appeal is fairly consistent with what Democrats have had when they win in Virginia, they have some crossover appeal,” said Mark Rozell, a political scientist at George Mason School of Public Policy. Virginians, Rozell added, are looking for something new. “His promise of a fresh face, somebody new, has some appeal nationally and certainly here in Virginia,” he said.

While Obama has strung a series of wins together, the Clinton campaign has been beset with setbacks. The day after Super Tuesday, the campaign disclosed a $5 million loan Clinton made to the campaign, a sign that what was once a hefty campaign war chest had been depleted. Then last Sunday, campaign manager Patti Solis Doyle resigned. Maggie Williams, another long time Clinton insider, has taken over as campaign manager.

From here, the Democrats will head to Wisconsin and Hawaii on Feb. 19. Hawaii is a home state for Obama, so he is expected to do well.  

Polling suggests Clinton may be able to hold off the Obama momentum in Wisconsin, where there are more blue collar workers, a significant part of her base, and less African Americans, who overwhelmingly support Obama. On March 4, Texas, Ohio, Rhode Island and Vermont will hold contests.  

That day will be crucial to the Clinton campaign; in Texas, she will need to prove her support among Hispanic voters has not diminished and, in Ohio, she will need blue collar workers to support her. Finally, the Pennsylvania primary will be April 22 and may be Clinton’s last shot. Due to Democratic primaries allotting delegates proportionally, it is unlikely either Obama or Clinton will earn the 2,025 delegates needed to secure the nomination before the convention. In that case, Super Delegates will determine who the nominee will be.

But while things for Clinton may look dire, Sabato notes the Democratic race has been fluid this year so he doesn’t count her out. “Clinton has got to make March belong to her, mainly by means of the Ohio and Texas primaries on March 4,” he said. “This has been a seesaw contest, so who can say this wont happen again? Texas may either be Clintons firewall or her Alamo.”