What happened
Hillary Clinton won the Pennsylvania Democratic primary, beating Barack Obama, 55 percent to 45 percent. Clinton led by as much as 20 percentage points in early polls, but Obama cut the lead to single digits as the vote neared and heavily outspent Clinton in the race. Clinton hailed the win as a sign that she is more electable, and vowed to keep on running through the nine remaining primaries. (Reuters)

What the commentators said
Clinton "unquestionably met or exceeded expectations,” said Noam Scheiber in The New Republic’s The Plank blog. But “the bottom line” is that she “needs an Obama meltdown” if she has any real hope of capturing the nomination. And even with “all the uproar about Jeremiah Wright and bittergate,” she didn’t get that in Pennsylvania.

No, but Pennyslvania Democrats did throw Clinton "a much-needed lifeline," said Dan Balz in The Washington Post (free registration). Her "path to the nomination remains extraordinarily treacherous," and even some of her most loyal supporters admit privately that they don't like her chances. But she now has "fresh incentive" to soldier on.

The Obama campaign will argue that Pennsylvania's results "change nothing” in the Democratic race, said Michael Goldfarb in The Weekly Standard’s The Blog, and that’s “entirely true.” But that means the real damage done to Obama in Pennsylvania was essentially “needless,” and his supporters “have to be crying on the inside.” If Clinton does somehow “pull this thing out,” though, her “drinking beers, trashing MoveOn, and threatening to obliterate Iran” has done wonders in “softening her image among Republicans.”

That certainly won’t help the Democrats in November, said The New York Times in an editorial (free registration). Going “heavily negative” cost Clinton her “20-point” lead in Pennsylvania, and thus her much-needed “big win.” If she doesn’t switch from attacking Obama to engaging him on their minor policy differences, she’ll continue to turn off voters and Democratic superdelegates. It is “past time” for Clinton to “call off the dogs” and “acknowledge that the negativity, for which she is mostly responsible, does nothing but harm to her, her opponent, her party and the 2008 election.”

So why isn’t John McCain benefitting more? said Ross Douthat in The Atlantic’s The Current blog. Despite the “divisive, bitter, and seemingly endless” Democratic battle, the presumptive Republican nominee keeps on “bumping up against the same 45 percent ceiling” in national polls. Head-to-head polls now aren’t a great indicator of what will happen in November, but with “sky high” favorable ratings, conservative critics “making nice,” and opponents locked in a “fierce civil war,” this should be “a peak time for McCain’s numbers.” That it isn’t “doesn’t bode well” for him.