11:26PM - Here's the spin from the Obama campaign in a just released memo:

To: Interested Parties

Fr: The Obama Campaign

Re: A fundamentally unchanged race

Da: 4/22/08

Tonight, Hillary Clinton lost her last, best chance to make significant inroads in the pledged delegate count.

The only surprising result from Pennsylvania is that in a state considered tailor-made for Hillary Clinton that she was expected to win, Barack Obama was able to improve his standing among key voter groups since the Ohio primary. For example, among white voters, Obama narrowed the gap with Clinton by six points. Among voters over 60, he nearly cut the gap in half, from 41 points to 24 points. And Independent voters - the group that will decide the general election and a group Obama is particularly strong with - were not able to vote in Not surprisingly, she led by as much as 25 points in the weeks leading up to the election.

As he has done in every state, Barack Obama campaigned hard to pick up as much support and as many delegates as possible and was able to stave off Clinton from achieving a significant pledged delegate gain from Pennsylvania.

The bottom line is that the Pennsylvania outcome does not change dynamic of this lengthy primary. While there were 158 delegates at stake there, there are fully 157 up for grabs in the Indiana and North Carolina primaries on May 6.

The problem for the Obama campaign is that it's not necessarily about the pledged delegates right now. Clinton is going to net 200,000+ in the popular vote count tonight, getting her very much back on track to catching Obama, especially when Florida (and, on a stretch, Michigan) is included in the tally. She's also successfully turned the narrative to the question that many people - but most especially super delegates - are asking tonight, which is: why can't he close the deal? He spent $11 million in Pennsylvania and got his clock cleaned. That is not something that can be spun away easily, and it will cause any nagging doubts about his candidacy to grow over the next few days as the super delegates and the media digest what went down tonight in the Keystone State. - TOM BEVAN

10:44PM - "The tide is turning," Hillary said, concluding her victory speech. As Jay noted, we likely won't know the final margin until tomorrow, but right now Hillary is up 10 points with 78% reporting. If she can hang on to 10, that seems like a convincing victory.

But the Clinton campaign will likely trumpet another number: It seems that come tomorrow Hillary will lead in the popular vote count (if one includes Michigan and Florida). - BLAKE DVORAK

10:11PM - More non-Pennsylvania news: Southaven, Mississippi Mayor Greg Davis, a Republican, is within a few hundred votes of winning a special election to replace now-Senator Roger Wicker, a fellow Republican. With 88% of precincts reporting, Davis has 49% of the vote compared with 46% for Democrat Travis Childers. That's not encouraging news for Republicans, though. President Bush won the seat by 25 points in 2004. If Davis does not reach 50% tonight, he and Childers will meet in a May 13 runoff. - REID WILSON

10:00 PM - The vote returns have begun to trickle in, and we're getting a sense of how the race is shaping up. Obama is doing extremely well in Philadelphia County. He's up by 22 points. The trouble for him is that more than 75% of the county has reported. In Delaware County, also in metropolitan Philadelphia, Clinton has fought Obama to a draw so far. In Bucks, few precincts have reported, but Clinton has a modest lead. Chester and Montgomery counties have yet to report at all. The size of Clinton's victory will not become apparent until then. Outside of Philadelphia, Clinton is doing exceedingly well. She's dominating Obama in metropolitan Pittsburgh, including a 12% lead (so far) in Allegheny County. She's up 24 points in Erie County and up in Lackawana County, where Scranton is.

If you are interested in waiting for the whole state to return, expect to be up late. The central part of the state is notoriously slow. - JAY COST

9:15PM - Here come the trumpets:

"There's beginning to be a subtle shift of psychology of a lot of the uncommitted supers," [Clinton spokesman Mo] Elleithee said. "[They] are beginning to wonder why Obama has been unable to win these thing despite all the advantages he has," Elleithee said.

"There's a lot of questions that are beginning to surface about him," he said, while superdelegates are learning that "every time she's got her back up against the wall, she delivers."

Spinning aside, Obama did put a lot of resources into this state. So it'll be interesting to hear the Obama spin. - BLAKE DVORAK

8:55PM - Not an immediate call, but not a late call either. So the question now becomes: By how much? Earlier today NBC's Chuck Todd said that anything more than 7 points is not good news for Obama. While Obama certainly can boast halving a 20-point deficit, Clinton's argument that he can't win the big states becomes stronger. As Todd said (with maybe just a degree of overstatement) it would reveal a "fundamental problem." - BLAKE DVORAK

8:52PM - In non-Pennsylvania news, the Supreme Court heard arguments today on the so-called Millionaire's Amendment, which we previewed yesterday on Politics Nation. As The New Republic wrote, former candidate Mitt Romney came in for some criticism. "Mr. Chief Justice, they are interested in those candidates only inasmuch as they get elected. The moment that the public turns on them, they won't be interested. And certainly the public was not particularly interested in Mitt Romney, who spent a significant amount of money on his own behalf, and many other spectacular flameouts," plaintiff's attorney Andrew Herman told the Court. Laughter ensued, the transcript showed. - REID WILSON

8:50PM - NBC called it too. - TOM BEVAN

8:45PM - FOX called it for Hillary. NBC still has it too close to call. CNN is on commercial (UPDATE: CNN still not calling). - TOM BEVAN

8:23PM - Obama's big margins in Philly and the surrounding burbs can be attributed to turnout wizard Tom Lindenfeld, a consultant in Washington who is a former partner and close friend of Obama strategist David Axelrod. Lindenfeld, a native of neighboring New Jersey, has close ties to big labor and is an experienced organizer who has, among other things, managed the floor show at the last several Democratic National Conventions. Lindenfeld's firm, LSG Strategies, assisted Obama when he was an underdog in his bid for the Democratic Senate nomination in Illinois. - REID WILSON

8:19PM - According to CNN exits, Obama led Clinton 69%-31% in Philly and 62%-37% in Philly suburbs. Clinton led 66%-34% in Northeast Pa. and 61%-38% in Pittsburgh and the western part of the state. In Central and Northern Pa., the race is close, with Clinton up 52%-48%. Statewide, Obama led among male voters 53%-47%, while Clinton led females 55%-44%. - KYLE TRYGSTAD

8:01PM - No quick call from CNN, MSNBC or FOX. What does that tell us about Clinton's potential margin of victory? Could be a problem. Then again, Ohio wasn't a quick call either and she ended up winning by ten. - TOM BEVAN

7:48PM - With just over 10 minutes until polls close, a PA Common Pleas Court judge has rejected a request to extend Philly polling hours.

Elsewhere, Obama is scheduled to touch down in Indiana at 9:45 tonight. Good sign, bad sign -- no sign? We'll see shortly. - BLAKE DVORAK

7:15PM - Here are some numbers to keep in mind as tonight's results come in. There are 4.2 million registered Democratic voters in Pennsylvania. Of those, 800,000 (about 20%) reside in Philadelphia alone, and another 700,000 are in the the Philly suburbs of Bucks, Chester, Delaware and Montgomery counties. So more than one-third (36%) of the state's registered voters reside in Philly and its suburbs. Adding in the outer-ring counties of Lancaster, Berks, Lehigh and Northampton (a total of some 400,000 voters), the greater Philadelphia area makes up about 46% of the state's registered voters. - KYLE TRYGSTAD

7:06PM - Two factors to watch tonight: The thousands of new voters -- 215,000 in Philadelphia alone -- who break heavily for Obama, versus what looks like a hard ceiling at 45%. No poll in Pennsylvania has shown Obama above that mark. So, do new voters push Obama over the top and into what the media will consider a winning position, or does his hard ceiling help Clinton break out a big win? - REID WILSON

7:00PM - This new SurveyUSA poll is sure to give some Democrats heartburn. The poll shows that 59% of Democrats say Clinton should remain in the race if she loses in Pennsylvania, while 39% say she should drop out. Independents feel the same, by a margin of 54 to 40. Interestingly, more Republicans think Clinton should drop out (48%) if she loses tonight, while an equal number (49%) say she should stay in the race. - TOM BEVAN

6:49PM - Gary Langer of ABC News has a write up of the exits that would, at first blush, appear to be positive for Clinton:

Preliminary results indicate that nearly six in 10 voters are women, which if it holds in final data will be a high for Pennsylvania, though about what it's been in all Democratic primaries this year. Turnout among African-Americans could be lower than it's been overall this year; it'll take updates later tonight to see whether it does or does not exceed the Pennsylvania primary record, 17 percent in 1988 and 1984.

Lots of time left, of course. Polls don't close for over an hour, at which point the picture will start becoming much more clear. - TOM BEVAN

6:35PM - CNN: "Sen. Barack Obama scored big with new Democrats in Pennsylvania, early exit polls show. One out of every seven Democratic party voters was not registered as a Democrat at the beginning of the year, and 60 percent of them cast their ballot for Obama, according to the exit polls." Sounds like Operation Chaos may have been overwhelmed. - TOM BEVAN