Susan J. Demas: Why Republicans have lost their moderates, but Democrats haven't

Long before the Tea Party existed, I had a ringside seat into the GOP's right-wing lurch.

It was the sweltering summer of 2006, and a sleepy Michigan congressional district was a test case for the conservative Republican cause.

The MI-7 was a solidly Republican swath of south-central Michigan, including industrial Jackson, three socially conservative border counties and moderate Lansing and Ann Arbor suburbs.

It was represented by freshman Joe Schwarz (R-Battle Creek), who had an absurdly impressive resumé: Harvard-trained surgeon, Vietnam veteran and CIA spy (he taught Indonesian President Suharto English, for God's sake).

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