With progressive darling Sen. Russ Feingold now in serious danger of losing his Wisconsin Senate seat, liberal activist group MoveOn.org is snapping into action. Moments ago, it sent the following email to supporters:

Dear MoveOn member,

Red alert: The latest polls show that Senator Russ Feingold could lose in November. They all have him down by at least 6 points against a tea party Republican who actually thinks climate change is caused by sunspots.
There’s no better, more principled Democrat in Washington than Sen. Feingold: The only senator to vote against the Patriot Act. A steadfast opponent of the wars in Iraq and Afghanistan. And a passionate crusader against corporate influence in politics.

But since those very corporate interests have already spent $650,000 trying to defeat him, he’s now facing the fight of his political life.  Because keeping Sen. Feingold’s voice in the Senate is so important, this race has become our top national priority.

Sen. Feingold’s campaign is up against a critical fundraising deadline that expires tomorrow. Right now he urgently needs the resources to expand his grassroots campaign, reach out to more voters and get his message out in Wisconsin. We’re aiming to raise $300,000 for Sen. Feingold’s campaign before the deadline. Can you chip in $5?

In what was once considered a safe seat for Democrats, Feingold now trails Republican Ron Johnson by an average of roughly 8 points, according to a compilation of polls by Real Clear Politics.