For one thing, no more Mr. Nice Guy, says Jonathan Weisman:

"Unable once again to score a knockout, Sen. Barack Obama is likely to make his new negative tone even more negative -- with a sharp eye on trying to end the Democratic presidential nomination fight after the May 6 primaries in Indiana and North Carolina. Sen. Hillary Rodham Clinton's victory yesterday in Pennsylvania has only accentuated the quandary that Obama faces: Stay negative and he risks undermining the premise of his candidacy. Stay aloof and he underscores Clinton's argument that he will not be able to beat a 'Republican attack machine' sure to greet him this summer ... Obama himself took up the cudgel after Clinton delivered a victory speech in Philadelphia devoid of attack lines. Without naming Clinton, he suggested in Evansville, Ind., that she is a captive to the oil, pharmaceutical and insurance lobbies, that she 'says and does whatever it takes to win the next election,' and that she exploits division for political gain."

You call that a cudgel? That's barely even a switch.

... "Hillary Clinton scored a big victory in Pennsylvania on Tuesday to keep her hopes for the Democratic nomination alive. The question is whether the win came soon enough ... It's doubtful that Clinton can overtake Obama in North Carolina; he has won all the southern states and their large black populations except for Arkansas, where Clinton was first lady when Bill Clinton was governor. But part of the reason the Clintons will campaign in North Carolina is to make it necessary for Obama to spend more time there and away from Indiana, where polls show a tight race."

... Of course, the opposite might be true, too:

"Obama has forced Clinton to chase him with spending, forcing her hand early by eroding her leads in public opinion polls. Clinton once led in Indiana, but Obama now holds a narrow edge in some polls. Depending on how well she can parlay Tuesday's victory into cash, some Democratic Party strategists believe Clinton may have to shift her money out of North Carolina and into Indiana in hopes of staving off two losses in one day."

Our prediction -- she spends money in North Carolina early to keep Team Obama honest, then dumps everything into Indiana in the final days.

... In either event, Hoosier fans best brace themselves for an onslaught of ads and visits:

"Presidential politics hasn't been this intense in Indiana since 1968. Indiana, he said, will be getting a taste of what New Hampshire, which holds the nation's first primary, experiences every four years. There, folks take it for granted that they'll be able to judge the candidates in person ... Clinton and Obama have been in Indiana a lot already. Counting today's visit, Clinton will have made 15 stops in 12 cities. And the entire Clinton family -- including former President Bill Clinton and daughter Chelsea -- will have made 50 campaign stops in the state. Obama and his wife, Michelle, have made 14 stops in 14 Indiana cities so far."

Well played, Gov. Rendell

It's your classic win-win situation for the governor, supposing he has national ambitions:

"Sometime last week, Gov. Rendell spoke his one millionth word on television for U.S. Sen. Hillary Clinton. She carried his state last night. But suppose U.S. Sen. Barack Obama is the party nominee. Is Ed screwed? Are his hopes for serving in a presidential cabinet some day lost? Probably not, for a few reasons. First, if Obama is the nominee, Rendell will still be governor of a key state, and he'll have his chance to win Barack's heart with all the frenetic fundraising, press-spinning and barnstorming he's known for. Second, insiders say that Rendell will likely become chairman of the bipartisan National Governors Association later this year, making him a player in Washington no matter who wins the presidency."

Hill and Bill

The New York Times sees a Pyrrhic victory, given that what once was a 20 point lead was halved in a matter of weeks:

"The Pennsylvania campaign, which produced yet another inconclusive result on Tuesday, was even meaner, more vacuous, more desperate, and more filled with pandering than the mean, vacuous, desperate, pander-filled contests that preceded it. Voters are getting tired of it; it is demeaning the political process; and it does not work. It is past time for Senator Hillary Rodham Clinton to acknowledge that the negativity, for which she is mostly responsible, does nothing but harm to her, her opponent, her party and the 2008 election ... Mrs. Clinton did not get the big win in Pennsylvania that she needed to challenge the calculus of the Democratic race. It is true that Senator Barack Obama outspent her 2-to-1. But Mrs. Clinton and her advisers should mainly blame themselves, because, as the political operatives say, they went heavily negative and ended up squandering a good part of what was once a 20-point lead."

... So you're saying you're a fighter?

"Indeed, in her victory speech in Philadelphia on Tuesday night, Mrs. Clinton used the words 'fight,' 'fighter' and 'fighting' repeatedly -- not only to promise financially struggling Americans that she would protect them, but also to convey that she had the resolve and confidence to stay in the race."

Obama-rama

Hillary "needed" to win big in Pennsylvania. Does Barack "need" to win big in North Carolina?

"Not so long ago, Harold Ford Jr. was the rising black politician within Democratic ranks. Now he heads an arm of the party that seeks to keep its focus on middle America and crafting centrist messages: the Democratic Leadership Council. Often vilified by liberal activists, the DLC sees itself as quintessentially practical. From that perspective, and in the wake of Hillary Clinton's win in the Pennsylvania primary, Ford just set a political bar for the black politician that surpassed him in prominence. 'You have to win Indiana,' Ford told Barack Obama (via an interview on MSNBC). And, Ford added, Obama has to 'steamroll' Clinton in the other state with a primary two Tuesdays from now, North Carolina. The Obama camp will not publicly embrace that equation. But for him to truly regain the momentum he captured during his February surge, most party pros will see Ford's formulation as spot-on."

Here's the video.

... The latest spin from Obama HQ:

"In a conference call with reporters this morning, Obama campaign manager David Plouffe argued that Clinton's win in Pennsylvania yesterday doesn't change the current trajectory of the race: -- Obama leads among pledged delegates, and Clinton will have to win about 70% of the remaining ones to overtake Obama on this measure. -- to get within 100 pledged delegates of Obama, Clinton will have to win 57% of the remaining ones -- and when looking at the total delegate score (pledged delegates and superdelegates), Obama is about 300 away from clinching the nomination; Clinton, according to NBC's count, is more than 430 delegates away."

Congratulations, Pennsylvania ...

On setting a new primary voting record, says Capitolwire.com:

"State turnout record broken by almost 50 percent, as 700,000 more cast votes Tuesday than in any other Pa. primary. The Pennsylvania record for primary turnout was set in 1980, at 1.53 million. It stood for 28 years, and then got broken into tiny little bits."

... Voters helped Hillary not only close the delegate gap, but also Obama's lead in the popular vote.

More to come.