http://www.theatlantic.com/politics/archive/2008/03/off-message/43797/ Pennsylvania's perennially close, but when you look at a state that went Democratic in the last four presidential elections and hasn't shown any underlying pro-GOP trend, it seems unlikely that any Democrat would lose it in a generally favorable political climate for Democrats.
This article available online at:
http://www.theatlantic.com/politics/archive/2008/03/off-message/43797/
