Hillary Clinton won a decisive ten-round decision over Barack Obama in Pennsylvania’s Democratic primary, but she didn’t score a knockout. The struggle continues. Clinton still has virtually no chance of overtaking Obama’s delegate lead or his edge in the popular vote. And the superdelegates will be loath to ignore this advantage. Meanwhile, Obama’s weaknesses as a general election candidate grow more apparent with each successive primary.

Clinton’s best chance of winning the nomination was to win Pennsylvania so decisively that she would have set off a media firestorm about Obama’s electability--one that would lead superdelegates to wonder whether she would not be a much, much stronger candidate in November. In the wake of revelations about Obama’s relationship with Pastor Jeremiah Wright, Clinton was ahead by 15 percent or more in polls. I visited Pennsylvania during this time, and could feel the growing disillusionment with Obama.

Obama, of course, cut into Clinton’s lead through outspending her two-to-one on advertisements, but Clinton seriously damaged her own cause by going negative on Obama during the April 16 debate--and probably, too, by her subsequent ads. ABC moderators George Stephanopoulos and Charles Gibson had already done sufficient damage without Clinton piling on. According to the exit polls, 68 percent of Pennsylvania Democrats thought Clinton attacked Obama unfairly, and they backed Obama by 55 to 45 percent. It’s hard to know for sure, but these tactics probably cost her among white college-educated voters who don’t like to think of elections as prize fights. (The editorial in this morning’s New York Times, entitled “The Low Road to Victory,” reflects this dissatisfaction with the way Clinton conducted herself.)

For his part, Obama cut into Clinton’s advantage, but couldn’t erase it. Even though he campaigned extensively among white working class Pennsylvanians, he still couldn’t crack this constituency. He lost every white working class county in the state. He lost greater Pittsburgh area by 61 to 39 percent. He did poorly among Catholics--losing them 71 to 29 percent. A Democrat can’t win Pennsylvania in the fall without these voters. And those who didn’t vote in the primary but will vote in the general election are likely to be even less amenable to Obama.

But Obama also lost ground among the upscale white professionals that had helped him win states like Wisconsin, Maryland, and Virginia. For instance, Obama won my own Montgomery County, Maryland by 55 to 43 percent but he lost suburban Philadelphia’s very similar Montgomery County by 51 to 49 percent to Clinton. He lost upscale arty Bucks County by 62 to 38 percent.