In Pennsylvania, longtime Republican strongholds in counties throughout the state are slowly shifting away from the GOP.

On Thursday, in Dauphin County -- which includes the state capitol of Harrisburg -- the numbers of registered voters looked like this: 81,489 Democrats and 81,340 Republicans.

In Philadelphia suburbs like Bucks and Montgomery counties, the trend is the same.

Waves of new Democratic voter were registered during the heated primary contest between Sens. Barack Obama and Hillary Clinton. That month of intensive campaigning certainly helped to put some areas over the top.

But this change is part of a longer-term demographic trend, and the end of the primary hasn't stopped the movement:

Statewide, Democrats have added voters since the April 22 primary, picking up 37,529 registrations while Republicans have lost 1,504, according to figures from the Pennsylvania Department of State [...]

From November 2007 to April's primary, the Republican Party lost 58,119 registered voters.

We still have a lot of work to do between now and November to maintain our control of the Penn. House, but information like this is heartening.