For the last few weeks, a common refrain has come from the campaign of Sen. Hillary Clinton, namely that Obama's victories were the product of overwhelming numbers of black voters, that he was winning in caucuses dominated by party activists, that he was not winning in "big" states or because of women's votes.
Republicans have a different issue. They have a clear winner in McCain, but he continues to be embarrassed by his remaining challenger, Mike Huckabee, whose strong showings underscore McCain's weakness with the religious conservative base of his party that doesn't seem willing to accept the new reality.
In Tuesday's Potomac primary, Obama and McCain came away with victories, but it was the strength and breadth of Obama's that was most notable. He won majorities of women, won sizable numbers of blue-collar votes and captured nearly half the votes of all whites.
McCain's unimpressive win over Huckabee in Virginia laid bare that the Arizona senator has yet to persuade religious conservatives in his party, a group that he needs in order to prevail in November.
Obama's easy wins in Maryland and the District of Columbia had been expected; his sweep of Virginia was perhaps the best measure of the upward trajectory of his candidacy. Maryland proved to be a routine victory lap for McCain as well.
Though the Clinton campaign insists that Obama's wins are small bore, Obama kept counting something else -- victories, now eight straight, and delegates. By almost any objective measure, he has pulled ahead. Obama also holds undisputed possession of a powerful sense of momentum and energy, while Clinton's campaign is walking with a limp.
"He is winning coast to coast and showing strength with groups that one would assume would be for his opponent," said Sen. Dick Durbin of Illinois, an Obama supporter.
That was particularly true in Virginia, a state with rapidly changing demographics where Democrats would like to compete aggressively in November.
Obama won with nearly every major demographic group. He seems poised to add to his streak next Tuesday with contests in Hawaii, where he grew up, and in Wisconsin, where he is leading. He plans a speech on Wednesday in Janesville, Wis., where he will address economic issues and try to connect better with working-class white voters who have helped sustain Clinton in states where she has won.
Eye on March 4 primaries
Clinton was already in Texas when returns of the Potomac primary were known, the clearest indication that she has staked her campaign on winning there and in Ohio on March 4.
"It's all going to come down to March 4," said Chris Lehane, a Democratic strategist and Clinton supporter. "What's going on here is that you have some very distinct voting blocs, the Dunkin' Donuts coffee-drinking Democrats [for Clinton], and Obama has the latte-sipping Democrats and African-Americans.
"Neither has transcended their voting profile," he said.
At least not before the returns were counted in Virginia, where Obama did break out in several important areas, but perhaps most significantly among women and blue-collar workers.
McCain has no similar wind at his back, but his journey to the nomination is nonetheless all but assured. His problem is that the Democrats seem to be expanding their pool of voters while Republicans are not.
Democrats have not rallied behind a single candidate yet, but they are rallying nonetheless with levels of enthusiasm that the GOP to date cannot match.
If Huckabee stays in the race much longer, he will only continue to spotlight McCain's weakness, something that cannot be encouraging to Republicans on the day their nominee became most clear.