David makes an interesting point today:

Republicans are instinctively sympathetic to Lieberman as a Democrat who demonstrates that one can remain faithful to liberal principles at home while supporting the country’s war effort abroad. That said, it might prove something less than an unmitigated catastrophe for the Republic, the war, and (ahem) the GOP if Lieberman were to lose. His defeat would hand Republicans a vivid symbol of what the Democratic party is evolving into: It’s too left-wing, too defeatist, too antiwar even to tolerate its own vice presidential nominee of six years ago! Even the George McGovern Democrats never mounted a primary challenge to Hubert Humphrey! 2006 will be a tough year for Republican incumbents. But the Democrats are doing their best to level the playing field by presenting themselves as the party of amnesty for illegal aliens and surrender to jihadists in Iraq. Can Rick Santorum use that talking point? I bet he can.

I write about Lieberman here.