Eastern Pennsylvania has been a key battleground in the struggle for control of the House -- witness the DCCC's massive expenditure yesterday targeting GOP Rep. Mike Fitzpatrick. But now the contested terrain is spreading to Western Pennsylvania, too, reports CQ Politics. As a result, CQ has just changed its rating of the race between GOP Rep. Melissa Hart and Dem challenger Jason Altmire from "Republican Favored" to "Leans Republican." More of CQ's analysis after the jump.

CQ Politics:

As in many House districts in this difficult election year for the Republicans, national GOP officials unintentionally signaled the more uncertain outcome by rushing in resources and airing television advertisements in the 4th District, which takes in suburbs and exurbs of Pittsburgh — and which backed President Bush in 2004 by 54 percent to 45 percent.

According to a filing with the Federal Election Commission, the National Republican Congressional Committee (NRCC) on Tuesday reported spending $163,000 to produce and air a television ad opposing Altmire — one day after the House GOP campaign committee reported spending $10,569 to poll the district...

A big question for Altmire is whether he can persuade independent and Democratic voters who lean to the right on social issues to back him after they previously supported Hart, albeit over weak past Democratic opponents. Altmire expresses a socially conservative side, opposing abortion rights and gun control measures.

Hart’s campaign and Republican supporters nonetheless have branded Altmire as a “Howard Dean Democrat” ever since the Democratic National Committee chairman — a socially liberal former Vermont governor and 2004 Democratic presidential hopeful — campaigned with Altmire a few months ago.

Altmire dismissed the arguments as “crazy,” noting that a liberal Democrat he defeated in the May primary election had accused him of being too conservative.

“I’m pro-life. I’m pro-gun. And one of the things that I never thought I would be called in this race is ‘liberal,’” Altmire said. “But I guess when the race is not going well, those are the kind of things you resort to.”

It's races like these -- once out of play, but now moving into the competitive camp -- that make the question of just how deep the national Democratic Party should dig into its pockets looms ever larger.

Update: In other ratings changes, CQ Politics has also changed its ranking of the race in Nebraska's Third District between Dem Scott Kleeb and GOPer Adrian Smith from "Safe Republican" to "Republican Favored."