FROM JAMES TARANTO, more on why the Left needs racism.

Carlson’s whole appeal to emotion actually cuts against her argument. No doubt the Jim Crow scenes in “The Butler” are shocking. But in 2013, that is the shock of the unfamiliar. If blacks were still oppressed in the South, you wouldn’t need to go to the theater to see it. You could watch it in high-definition in your living room, on the evening or cable news.

The Carlson piece got us to thinking about why race plays such a central role in the worldview of today’s liberal left, and why those on the left seem to suffer from a compulsion to exaggerate wildly the continuing prevalence of racism. In the first two columns in this series, we argued that it serves a political purpose, sustaining black loyalty to the Democratic Party, and a psychological purpose, allowing white liberals to assert their moral supremacy over other whites. (Since we wrote the latter column, it has also occurred to us that the idea of “white privilege” seems to be a guilty pleasure for some whites.)

Carlson’s argument suggests a third purpose, an ideological one.

It has now been 49 years since Congress passed the Civil Rights Act and 48 since the Voting Rights Act. If racism really remained as prevalent as liberals claim, one could argue that would represent a failure of liberal governance. Contrariwise, if indeed racism has largely abated, as this columnist asserts, that would seem to be a vindication for liberal governance.

But actually the liberal position is not inconsistent. Carlson does not deny the efficacy of the Voting Rights Act; rather, unfamiliar with its actual workings, she takes it as an article of faith that without it, even in 2013, blacks would be forbidden from voting.

When you’re that ignorant, you take a lot of unlikely things on faith. Especially when they’re ideologically convenient.