We like to use the term “swing district” to describe an area where the two major parties are matched pretty evenly, according to recent election history.

Chances are we’ll be invoking that phrase when describing what should be a competitive 2010 campaign in Pennsylvania’s 3rd District, a swath of in northwestern and western communities where Republican Rep. Phil English was defeated last year by Democratic challenger Kathy Dahlkemper. She won by about 7,100 votes and a margin of 2 1/2 points.

But Dahlkemper’s narrow win seems like a landslide next to the presidential balloting in her district. According to a CQPolitics.com analysis,