For liberals, the great mystery of the last few decades is how Republicans usually have won enough votes to control one or both houses of Congress even as the party moves increasingly to the right. As political-science profs Jacob Hacker and Paul Pierson put it in their 5,500-word article in the spring issue of The American Prospect, “In a 50-50 nation, Republicans have learned how to have their extremist cake and eat it too.”

Hacker (of Yale) and Pierson (of UC Berkeley) contend that there are two major reasons why the GOP has been able to “mak[e] American politics ever more dysfunctional while largely avoiding accountability for its actions.” One is that our system of government, with its “dispersal of authority,” makes it hard for voters to see which party is causing the trouble. The other is that our “often-feckless news media” have routinely failed to enlighten the public that “Republicans are primarily responsible for polarization and deadlock” and that GOPers have engineered “an ongoing massive shift of…the ‘center’ of American politics…toward the anti-government fringe.”