Potomac Primaries

WASHINGTON (CNN) — Call it the political Battle of the Potomac: today is primary day in Virginia, Maryland, and the District of Columbia — an unaccustomed star turn for a region defined by national politics but rarely courted by presidential hopefuls.

Coming off of his clean sweep of Hillary Clinton in the five Democratic contests this weekend, Barack Obama will be aiming for a political hat trick Tuesday. The area is home to large populations of African-Americans, affluent and well-educated voters - all voting blocs that have turned out at the polls in huge numbers for Obama so far this year. And Virginia allows independents - who have also gone for the Illinois senator by significant margins this cycle - to vote the state's Democrat contest.

In short: today's Potomac Primary seems demographically tailor-made for the Illinois senator.

Yesterday, Clinton downplayed Obama's weekend victories. And in conference calls and campaign memos, her team was still looking past the miserable month of February, which has so far delivered a string of losses, the revelation of short-term fund-raising headaches, and a headline-grabbing leadership shuffle. March 4 seems to feature some friendlier demographic terrain, at least, with a significant union and blue collar voting electorate in Ohio, and a heavy Latino presence in Texas - though the fact that both states allow independents to participate in the Democratic contest makes for a potential wild card.

(Still, the CNN delegate count - at least for the next few hours — gives the edge to Clinton: 1,148 to 1,121 over Obama due to her support from superdelegates).

On the Republican side, John McCain may be, statistically, the likely GOP winner — although he lost two contests this past weekend. The Arizona senator lost to underdog Mike Huckabee Saturday — by double digits in the Kansas caucuses, and in a squeaker in Louisiana. Even his lone victory came with a question mark, since 13 percent of the votes in the Washington state caucuses weren't counted - a decision Huckabee is challenging.

McCain may find some solace in results along the Chesapeake today, but the conservative unrest apparent in the weekend's Republican results would seem to raise major questions about his viability in the general election.

– CNN Deputy Political Director Paul Steinhauser