John Thune won in the closing weeks of the campaign because of the potency of two overlapping themes:

1) Daschle talks conservative in South Dakota but acts the opposite in Washington.

2) Daschle has lost touch with basic South Dakota values.

The issues that drove these two themes in the closing days were the Federal Marriage Amendment, Daschle’s patently false pro-life and pro-marriage claims, Daschle’s record of obstructionism – especially his blocking of President Bush’s conservative judicial nominees, and the brouhaha over Daschle’s official residency.

As NRO has noted, the 527 “You’re Fired” ran a massive television and radio campaign in the closing weeks of the campaign using Daschle’s opposition to the Federal Marriage Amendment to question whether Daschle’s “heart is still in the heartland.” That phrase became a shorthand expression for the growing perception that the answer was “no.” The ad also raised the specter of liberal activist judges – complementary with the judicial obstruction charges being raised by Thune and others. The ad also linked Daschle to “his pals in Hollywood” effectively touching on the idea that Daschle does not share basic South Dakota values.

Daschle’s campaign also took the threat from the marriage issue so seriously that they ran an “over-the-top” ad saying Daschle was both pro-life and pro-marriage. Most observers agree that this ad backfired on Daschle – since his record – particularly on the life issue was so extensively the opposite of his claims.

At the end of the day, Daschle lost because what he had been doing for years finally caught up with him – and same sex marriage was the new issue in the equation that finally drove it home.