Why Can't Barack Obama Close the Deal?

April 24, 2008 — -- The candidate who burst onto the national stage promising to bring red and blue states together is suddenly looking quite blue.

Sen. Barack Obama's second consecutive lopsided loss in a critical swing state has exposed soft spots in the support he's been able to secure.

The Illinois senator's had persistent problems in winning working-class, less-educated whites and Pennsylvania accentuated his seeming inability to connect with those voters.

While Obama remains the prohibitive front-runner -- with an effectively insurmountable lead in elected delegates -- those potential weaknesses among key demographic groups are fueling a fierce argument inside the Democratic Party over Obama's ability to win a general election.

The weaknesses constitute Sen. Hillary Clinton's last best shot at the nomination: convincing party insiders who serve as superdelegates that Clinton can turn out the voters who are critical to the Democrats' chances against Sen. John McCain, R-Ariz.

"The bar was set high in Pennsylvania and she got over it with room to spare," said Steve Grossman, a former Democratic National Committee chairman who is helping the Clinton campaign lobby superdelegates. "She's been able to build a broader coalition in each of the last three primaries. And I think that his [Obama's] coalition is more available to her than hers is to him."

Despite being badly outspent by Obama, the New York senator won a resounding, nearly 10-point victory in Pennsylvania on Tuesday.

It was a statewide Obama wipeout: He carried only seven of the state's 67 counties, primarily in the Philadelphia and Harrisburg areas in the southeastern portion of the state.

"In the big states that count -- that we must carry to win the Electoral College -- she's the best candidate," Pennsylvania Gov. Ed Rendell, a Democrat, said on a conference call with reporters Wednesday. "It was a victory virtually everywhere in the state. … This was an awesome victory, a landslide."

Clinton started making that argument to superdelegates in the immediate aftermath of the primary.