In the days before the Pennsylvania primary, undecided Democrats had a real opportunity to end the suspense and get Hillary Clinton out of the race entirely. Polls appeared to show that Barack Obama had that kind of momentum in the Keystone State, until his debate performance killed it. Instead, late breaking deciders supported Hillary by a 16-point margin and she won as handily as she did in Ohio and New Jersey, taking all but the most urban areas of Pennsylvania and exposing Obama as a poor closer once again:

Sen. Hillary Rodham Clinton won the Pennsylvania presidential primary decisively on Tuesday night, running up a 10-percentage-point victory that bolstered her case for staying in the race for the Democratic nomination.

Sen. Barack Obama played down a defeat that did not substantially reduce his delegate lead, but the outcome only further muddled a race that has stretched on for nearly four months and has sharply divided the party. The two will meet again in primaries in Indiana and North Carolina on May 6.

An estimated 2 million Democrats voted, nearly triple the number who turned out in the past two presidential primaries in the state. Clinton ran up big margins with her core constituencies, winning white voters with incomes under $50,000 by 32 points, voters over age 65 by 26 percent, and Catholic voters by 38 percent — more than countering Obama’s strong showing among black voters and higher-income whites in Philadelphia and its suburbs. She signaled that despite her dramatic financial disadvantage, she has no intention of getting out before the last votes are cast on June 3.

Obama’s campaign tried to spin the results as acceptable, basically arguing that a ten-point loss doesn’t amount to a landslide and therefore he kept Hillary from winning a moral victory. That doesn’t wash at all. Obama outspent Hillary 3-1 in Pennsylvania and he ended up at about the same place he was at after Ohio. One look at the county map in PA shows the problem. Despite spending tons of money across all of Pennsylvania, he only captured Philadelphia and parts of the suburban counties surrounding it.

Obama has quit resonating with white, working-class families, and small wonder why. After his Crackerquiddick comments and poor debate performance, he has left all but his true believers wondering who he is. Ties to unrepentant terrorists William Ayers and Bernadine Dohrn give Obama a radical flavor that negates his earlier assertions of centrism and independent thinking. At the very least, he looks inexperienced and vulnerable despite raising more money than anyone ever has before now.

David Lightman at McClatchy understood the implications as the results began to take shape last night:

Obama, on the other hand, stumbled badly. He outspent Clinton by an estimated 3 to 1. He had six weeks since the last primary to ingratiate himself with people he’s had a hard time wooing: blue-collar whites, small-town residents and older women. Instead, he once again lost the white vote handily and couldn’t put his opponent away.

The momentum that seemed so strong in February, when Obama won 11 contests in a row and seemed on the verge of knocking Clinton out of the race, was all but gone Tuesday.

Also gone, or at least fading, was the feeling among Democratic voters on both sides that either candidate ultimately would be acceptable.

While Democrats remain angry over the Iraq war, the economy and President Bush, they’ve grown less inclined to accept their favorite candidate’s Democratic opponent as a prospective president.

Democrats have discovered an ugly truth: neither of the two candidates left will unite the party, and for good reason. They’re both lousy candidates. People like Obama more on a personal level, but both carry significant negatives now, and both candidates have contributed to them. Hillary Clinton’s Tuzla Dash will guarantee her defeat in November, and if not, Bill Clinton apparently will. Hillary now gets less of the African-American vote than Republicans — only 8% in Pennsylvania. Obama can’t even buy a victory despite having more money than Croesus, and he has lost every big state the Democrats need to win in November.

We have a massive case of buyers remorse, and again we go back to the behavior of the undecideds. A compelling front-runner should have a large majority of late-deciders breaking his way, not away from him. Obama’s supposed inevitability should have swept him into victory at this late stage. If he can’t swing undecided Democrats, he won’t win independents or centrist Republicans in November against John McCain.

Update: Don Surber notes that Hillary has passed Obama in the popular vote, if Michigan and Florida get included.  Michigan shouldn’t count — Obama took his name off the ballot — but that “superdelegates should follow the popular vote” argument from Obama supporters may boomerang on them soon.