Last week, Karl Rove’s fundraising group, Crossroads GPS, made the first major ad buy in the Massachusetts Senate contest between Elizabeth Warren and Scott Brown. The ad is a vicious attack on Warren full of distorted images of the Occupy movement protesters and ungrounded claims.

The Nation’s Ari Berman joined Keith Olbermann on Countdown this Friday and explained why the Republicans view Warren as a threat. He also pointed out that the ad has backfired for Rove, hurting his credibility and providing an opportunity for Warren to rally support.

—Jin Zhao