Fiorina on Sorting and Polarization

At The Monkey Cage blog, Morris Fiorina writes:

What has happened in the United States is not polarization, but sorting. Prior to the 1980s the Republican Party had a significant liberal wing and the Democrats a significant conservative wing. People of my vintage can remember liberal Republicans like Gov. Nelson Rockefeller of New York and senators like Jake Javits [sic:  Jacob Javits hated the name "Jake." Friends called him Jack.] of New York, Hugh Scott of Pennsylvania, Charles Percy of Illinois, and Mark Hatfield of Oregon. No more. Similarly, the Democratic Party contained a slew of conservative southern governors, senators and representatives. In 1960 the greatest support for Civil Rights AND the greatest opposition to Civil Rights were both located in the Democratic Party, and in 1970 one would have been hard-pressed to say which party was more pro-choice. Today partisanship, ideology and issue positions go together in a way they did not in the mid-20th century. Issues and ideology used to cross-cut the partisan distribution, now they reinforce it.

But what about the data in the Pew Report? The opinion distributions in the report appear to show a decline in the center and movement toward the poles. Appearances are misleading however. The Pew distributions show consistency, not extremity. The authors of the report are very clear about the difference (sidebar p. 21), but many commentators have conflated the two. The confusion of the two concepts is fundamental and underlies virtually all the misconceptions about the findings.