Tim Fernholz reports on Joe Sestak‘s hunt for votes in the Philadelphia suburbs.

The residential communities of southeast Pennsylvania were for decades home to reliable, if moderate, Republican voters, but demographic shifts toward white-collar workers and minorities since 1988 as well as changes in the Republican Party have given Democrats an advantage. A concentrated effort among Democrats shifted the local rolls from a 20,000-voter Republican advantage in 2003 to a 13,000 Democratic advantage in 2008, Doylestown lawyer and Democratic activist Jordan Yeager told me.

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