The spread: Clinton needs to win by at least 10 percentage points -- the margin she posted over Obama in Ohio's March 4 primary -- to show that she has not lost her touch in the industrial Rust Belt, several uncommitted superdelegates said.
If she is successful, she will be able to point superdelegates to the fact that she trounced Obama despite being severely outspent on television and radio advertisements in Pennsylvania by a more than 2-to-1 margin.
If Obama can keep the race to within 10 percentage points, or even win, he would claim that he has shown surprising strength in a state that is Clinton's demographic home turf, with many of the lower-income Democrats who have supported her in earlier primaries. That kind of result would give Obama momentum heading toward the May 6 contests in Indiana and North Carolina, where a sweep would make a Clinton nomination feel all the more unrealistic.
http://www.latimes.com/news/politics/la-na-pennsylvania... Obama Set To Announce New Superdelegates After Pennsylvania Primary Obama strategists said Monday that they expected to announce a series of additional endorsements by uncommitted superdelegates shortly after Pennsylvania votes. A strong showing by Obama in Pennsylvania would give superdelegates more comfort in coming forward, but a bad loss might send them back to the assessment stage.
http://www.huffingtonpost.com/2008/04/22/obama-set-to-announce-new_n_97939.html