WASHINGTON — The battle between progressives and Fox News just got hotter. Liberal watchdog Media Matters has hired one of Glenn Beck’s key nemeses, a man who has been working behind the scenes (and more publicly on Twitter) for the past year to convince advertisers to drop the right-wing icon.

Angelo Carusone, a 28-year-old Long Island native and competitive debate champion, is a constant presence on Twitter under the moniker @StopBeck. He has leveraged his account to encourage other users to put pressure on companies to stop advertising on Beck’s show and update the Twitterverse on his successes. “Today, Helzberg Diamonds became the 302nd advertiser to drop Glenn Beck,” he wrote on Dec. 1, a day after he and others repeatedly sent messages to the company. His first victory came in August 2009, when Kraft Foods responded to him and said it did not want to be associated with Beck’s brand.

Through the efforts of Carusone and Color of Change (which was acting separately last year), hundreds of companies have told Fox News that they don’t want their ads to air during Beck’s program. In fact, in the U.K., his show has gone commercial-free for nearly eight months.