What is Fox News?

According to the impartial observers at Fox Business News, David Brock at Media Matters for America claimed earlier this year that Fox News is the "de facto head of the GOP." In fact, that was true in 2009-2010 when Fox fanned the flames of the Tea Party Movement and led the charge against Obama's health reform legislation. But I'm not so sure that Fox is still the only organizing force in the GOP at this point.