Robert Samuelson has a fine column on Bill Bishop’s interesting book The Big Sort. He points out that there is much to Bishop’s thesis that we have sorted into little red and blue enclaves — to cite just one statistic, 48 percent of counties went for one presidential candidate over the other by 20 points or more even though the national popular vote was split 51-48 — but concludes Bishop’s “argument is slightly overdrawn.” That’s my own view too, though I think aspects of Samuelson’s counterargument are overdrawn as well.

Samuelson counters that there is a greater difference of opinion between the ideological extremes in both parties than among the general public. Like Bishop, I think he’s on to something. The two parties are more homogenously ideological than ever before (even if principled liberals and principled conservatives could and should still criticize the Democrats from the left and the Republicans from the right) and that has made some people feel politically homeless. Both the Republican president and the Democratic Congress are deeply unpopular. Both major-party presidential candidates are having trouble getting more than 44 percent of the vote. But Samuelson’s examples of how the two parties ignore the “vital center” leave much to be desired:

Consider two decades of polls from the Pew Research Center. On many questions, there was little change. One question asked whether “government should care for those who can’t care for themselves.” In 1987, 71 percent agreed; in 2007, 69 percent did. Or take immigration. In 1992, when the question was first asked, 76 percent of respondents favored tougher restrictions; in 2007, 75 percent did. On some cultural issues, opinions converged. In 2007, only 28 percent thought school boards should be able to “fire teachers who are known homosexuals,” down from 51 percent in 1987. In 1987, only 48 percent thought it was “all right for blacks and whites to date each other”; by 2007, 83 percent did.

It’s not that everyone agrees on everything (divisions remain strong on the Iraq War, abortion, gay marriage). But growing polarization predominates among political elites of both left and right. The “Big Sort” of residential segregation is still reshaping the political landscape, though more indirectly. With fewer competitive congressional districts, the real political struggles now often take place in primaries, where activists’ views count the most. Candidates appeal to them and are driven toward the extremes.

But is precisely on the Iraq War, abortion, and gay marriage, the truly polarizing issues, that the two parties are divided. Neither the two parties, nor the left and the right, are divided over interracial dating, even if there are some outliers. Ronald Reagan opposed a ballot initiative that would have banned known homosexuals from teaching in public schools back in the 1970s; such a ban is hardly a major priority of any socially conservative elite today. Neither party is dedicated to the proposition that government shouldn’t help those who can’t take care of themselves, though they might have different definitions of who would actually qualify for help. The only issue Samuelson mentions where you could truly make the case that public opinion is being ignored is on immigration. But support for immigration restrictions tends to be labeled far-right, not centrist.