CNN: Analysis: Did Clinton's latest victory come in time?
By John Helton

Sen. Hillary Clinton and her daughter, Chelsea, embrace after Clinton's victory in Pennsylvania Tuesday.
(CNN) -- 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. Barack Obama's loss in another big state and the margins by which he lost among blue-collar and rural voters on Tuesday, on the other hand, may raise questions about his electability....
...(B)ecause Democratic delegates are allotted proportionally according to the vote, Clinton's Pennsylvania win does little to cut into Obama's lead among pledged delegates or his advantage in the popular vote count.
The results in Pennsylvania followed trends set in previous contests: Clinton won the white vote, Obama won the black vote; Clinton won the older vote, Obama won the younger vote; Clinton won in rural areas, Obama carried the urban vote. Look for Clinton to head into upcoming contests with the message that Obama can't win in the big states like Pennsylvania and Ohio that Democrats will need to regain the White House.
The focus is now on the next two contests on May 6: Indiana and North Carolina. Polls show Obama has a comfortable lead in North Carolina but Clinton won't give up on the state. Her husband, former President Bill Clinton, will be campaigning there on Wednesday. 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.
Obama needs a victory in Indiana to prove that he can win a large rust-belt state to bolster his case that he can carry the states needed to beat Sen. John McCain, the presumptive Republican nominee. Clinton has to cut into Obama's base to gain ground. And barring a major misstep by the Obama campaign, her best chance may hinge on attacking Obama and raising doubts in voters' minds. Clinton's challenging Obama's electability is also aimed at Democratic superdelegates, the elected officials and party leaders who are free to vote for whichever candidate they choose....
http://www.cnn.com/2008/POLITICS/04/23/primary.analysis/index.html