I think this is an interesting article by Dennis Roddy on the election results from last week. If nothing else, it does show the general weirdness of PA-12.
http://www.post-gazette.com/pg/10144/1060436-454.stm?cmpid=news.xml<snip>
Once again, a remote district in Appalachia's steel-and-coal belt declined to behave as predicted, opting to be less a mirror of national mood than a window into a unique corner of America.
Now analysts on both sides are struggling to identify precisely what happened in the sprawling 12th District, where Democratic candidate Mark Critz ran up an eight-point spread over Republican Tim Burns in the race to succeed the late John Murtha.
-snip-
That 2008 general election gave the often quirky 12th, with its 2-to-1 Democratic registration margin, not to Democrat Barack Obama but to Republican presidential candidate John McCain.
Those 2008 numbers, coupled with the 12th's profile as a seedbed of conservative, anti-abortion, pro-gun labor Democrats, raised hopes that the GOP could wrest control of a congressional seat that had been in Democratic hands since the Nixon administration.
<snip>