Limbaugh is particularly influential but hardly unique. Over the past few decades, conservatives have developed an infrastructure of media institutions that — with notable and principled exceptions — constitutes an ideological bubble. One may listen to Limbaugh at lunch, watch Sean Hannity in the evening and get Twitter alerts from the Drudge Report and Breitbart News all through the day. But these are not just sources of information; they are also businesses, particularly sensitive to the views of their audience. And what gets rewarded with listeners, viewers and clicks? Outrage at the perceived aggressions of liberalism. Anger at the compromises of the Republican “establishment.” And the defense of American identity against illegal immigrants and Muslims.

These positions can (and should) be debated on their own merits. But this much is undeniable: The market imperatives of conservative media institutions have nothing — absolutely nothing — to do with the health of conservatism, the success of the Republican Party, the election of a Republican president or solving serious national problems through principled compromise. To the contrary, conservative media outlets are incentivized to promote anger and discord, and to beat the hell out of mainstream Republicans. Some resist this incentive structure; most do not.