Big news, and perhaps a big leading indicator for Democrats in 2010: “Rep. John Tanner (D-TN), a leading Blue Dog Dem, will retire at the end of his current term, Dem sources tell Hotline OnCall.”

Back in October, I wrote:

Democrat John Tanner has represented Tennessee’s eighth district in Congress since 1989. The last time he faced serious opposition was 1994. He ran unopposed last year and won 99.97 percent of the vote. He is the epitome of a longtime, well-known, well-established Democratic Blue Dog with a wide-ranging network of connections and supporters.
Stephen Fincher is a farmer and gospel singer who has never lived outside of the perfectly named Frog Jump, Tenn. His biography prominently mentions his work as a Little League coach and performances in the family singing group since age nine. He is the epitome of a not-well-known, non-traditional, unlikely political candidate and longshot challenger.
Last quarter, Tanner raised $62,000. The gospel-singing farmer who’s never run for office before raised . . . $300,000.
Put this race on your must-watch list.

John Tanner took a long look at the gospel-singing farmer, and chose to retire.