Clinton's win brings new questions about race. "The Illinois senator won only 38 percent of the white vote in Pennsylvania on Tuesday, a big part of the reason he lost the state," McClatchy's Stephen Thomma writes. "Of the 30 states so far where voters were interviewed as they left polling places, Obama won the white vote in just seven, including his home state of Illinois."
"Why has he been unable to win over enough working-class and white voters to wrap up the Democratic nomination?" asks Adam Nagourney in The New York Times. "Lurking behind that question is another: Is the Democratic Party hesitating about race as it moves to the brink of nominating an African-American to be president?"
The New York Daily News' Michael Saul calls it the " 'bitter' aftertaste": "Blue-collar whites shunned Obama on Tuesday in the Keystone State, raising questions about his ability to attract the key voting bloc in a general election matchup with John McCain."
Bill Clinton is jumping on this theme -- keying off comments David Axelrod made on NPR Wednesday.
"Today her opponent's campaign strategist said, well, we don't really need these working class people to win, half the time they vote for Republicans anyways," the former president said in North Carolina, per ABC's Sarah Amos.
"And I will tell you something, America needs you to win, and therefore Hillary wants your support, and I hope you will help her in this primary in North Carolina."
McCain campaign manager Rick Davis likes what he sees: "The cracks in Obama's Democratic coalition in Pennsylvania mirror what we saw in Ohio, and those cracks could have implications in November," Davis writes in a memo.
The bottom line: Obama hasn't answered the questions that have swirled around his candidacy. "The data from last night suggests that voters believe that Hillary Clinton's argument about Barack Obama's general election viability will remain valid until Obama renders it invalid," The Atlantic's Marc Ambinder writes.
This is not the image Obama needs: "If you look at Obama's vote in Pennsylvania, you begin to see the outlines of the old George McGovern coalition that haunted the Democrats during the '70s and '80s, led by college students and minorities," John B. Judis writes in The New Republic. "Its ideology is very liberal. Whereas in the first primaries and caucuses, Obama benefited from being seen as middle-of-the-road or even conservative, he is now receiving his strongest support from voters who see themselves as 'very liberal.' "
But numbers can mislead: "For all of her primary night celebrations in the populous states, exit polling and independent political analysts offer evidence that Mr. Obama could do just as well as Mrs. Clinton among blocs of voters with whom he now runs behind," Patrick Healy writes in The New York Times.
"Obama advisers say he also appears well-positioned to win swing states and believe he would have a strong shot at winning traditional Republican states like Virginia."
And numbers are stubborn: "If this contest were still at the point where momentum, symbolism, and reading tea leaves mattered, Clinton would be in pretty good shape," writes National Journal's Charlie Cook. "Clinton is winning in big, important places, but it's happening about three months too late."
The line from Camp Clinton -- that she's ahead in the popular vote -- only works if you count Florida and Michigan (which superdelegates are smart enough not to accept on face value).