Jay Newton Small reports on the registration trends in Pennsylvania:

Although the final numbers are not yet in, so far registration has swelled 84,801 since the 2006 elections - that's 11% of the 790,000 people who voted in the 2004 Democratic primary. Last week alone 50,347 people became Democratic voters, according to Pennsylvania's State Department, bringing the state party's total to over four million for the first time ever. Since the beginning of the year, 86,711 Republicans and Independents have switched affiliations, and in just the last three weeks 34,104 new voters registered as Democrats. Significantly, 64% of those who changed parties were in the 12 largest counties - urban areas that have large African American and educated white populations, demographics that are Obama's strength. "I think he has a chance to pull off an upset here," said Ray Owen, professor emeritus of political science at the University of Pittsburgh. "The rates of changes in registration and new registrations indicate that some independents are joining the new voters in registering Democratic."

Jay fails to mention another factor that could be at play here: Rush Limbaugh. For weeks now Limbaugh has been imploring Republicans to re-register as Democrats and vote for Hillary Clinton in an attempt to extend the nominating contest thereby (theoretically) weakening the eventual nominee. Code named "Operation Chaos," Limbaugh took credit for pushing Clinton over the top in the popular vote in Texas and giving her a larger than expected margin of victory in Ohio.

Limbaugh has been pushing just as hard in Pennsylvania and the other remaining contests, so you have to believe a portion of those newly minted Democrats in the Keystone state are really Republican foot soldiers executing "Operation Chaos."