What happened
Hillary Clinton and Barack Obama made their closing arguments to Pennsylvania voters in a flurry of speeches and a barrage of TV ads, capping nearly two months of campaigning in the state ahead of Tuesday’s Democratic presidential primary. Clinton invoked Pearl Harbor and Osama bin Laden in a final commercial arguing that only she was prepared to be commander-in-chief. Obama responded by reminding that Clinton voted to authorize the Iraq war, and asking who voters wanted to answer "that 3 a.m. phone call: The person who got Iraq wrong or the person who got Iraq right?” (The Washington Post, free registration)

What the commentators said
“The Pennsylvania primary is crucial to Clinton's slim chance of survival,” said John Dickerson in Slate. The Clinton campaign is confident that Hillary will win big. And if the aftermath of her popular-vote wins in Ohio and Texas are any indication, the Clinton camp will “frame the victory as a ratification of her ‘Who do you think has what it takes?’ message (whether voters saw the last ad or not).”

It might seem like “a paradox,” said Peter Wallsten in the Los Angeles Times (free registration), but “the Clinton victory predicted by nearly all public opinion polls might actually turn out to be a loss if she doesn't win by a significant margin.” If Obama manages to keep the vote respectably close—losing the popular vote by a single-digit margin and keeping the division of delegates close—“he could be considered victorious.” But Clinton will have done long-term damage to his chances regardless of the vote margin if exit polls show she “succeeded in casting doubt on his credentials to be commander-in-chief or his ability to win support in the fall from white, working-class voters.”

“After one of the most negative weekends of campaigning so far this election,” said Jay Newton-Small in Time.com, “it's hard to know if either Barack Obama or Hillary Clinton will emerge from Tuesday's long-anticipated Pennsylvania primary looking much like a real winner.” They took their sniping to new depths in the hours before the voting, repeating “potshots” over Obama’s controversial pastor and Clinton’s imaginary sniper fire in Bosnia. “Viewers, and presumably voters, may want substance over scandal, but the two campaigns just can't seem to resist going for the knockout punch.”

That’s why there will be no winner in Pennsylvania, said David Kuo in BeliefNet’s J-Walking blog. “Clinton and Obama have destroyed each other, destroyed massive goodwill that millions of Americans had toward the Democratic party, and reminded everyone why they hate politics and politicians. It really doesn't matter who wins later today or by how much—both candidates are already losers . . . one just gets out of the race more quickly.”