Rush Limbaugh and the GOP

Rush Limbaugh insists that reports of advertiser defections have been exaggerated, but liberal groups say he's taking a lot of hits. It's all about Limbaugh's attack on Sandra Fluke, who testified on Capitol Hill about the need for health insurers to provide birth control to liberate women for the work force and protect against disease. Since Limbaugh attacked the Georgetown law student as a "slut" and a "prostitute," Democrats have accused Republicans of being insensitive to women's rights and issues. How much clout does Limbaugh have with the GOP?  Do candidates fear him?