In backing challenges to GOP moderates, the Tea Party looks like a looking-glass version of the "netroots" progressives who backed Howard Dean in 2004 and Ned Lamont's primary challenge to Sen. Joe Lieberman.
If Blanche Lincoln loses despite the endorsement of Bill Clinton and others, it will be another example of the democratic leadership being at least a step or two behind their party's electorate, even in a state like Arkansas.
If Blanche Lincoln and Arlen Specter survive the Democratic primary, it will only get worse. There is no guarantee Specter or Lincoln would beat their Republican challengers in November - in fact, odds are against it.
Tea Partiers will vote overwhelmingly Republican in November -- unless they stay home in protest. To gain their support, the GOP will have to nominate candidates who are less electable and more radical.