I was struck by this sentence in the Texas Fair Housing case (which I am only now getting a chance to read, thank you very much King v. Burwell):

De jure residential segregation by race was declared unconstitutional almost a century ago, Buchanan v. Warley, 245 U. S. 60 (1917), but its vestiges remain today, intertwined with the country’s economic and social life.

That is an important odd way of characterizing the holding in Buchanan v. Warley. Recall that this case was decided while Plessy v. Fergusson was still good law. It was most certainly not an equal protection decision. Rather it was a (gasp) economic liberty decision, based on similar doctrine applied in (gasp) Lochner. Consider the penultimate paragraph which discusses the holding:

We think this attempt to prevent the alienation of the property in question to a person of color was not a legitimate exercise of the police power of the state, and is in direct violation of the fundamental law enacted in the Fourteenth Amendment of the Constitution preventing state interference with property rights except by due process of law.

In class, echoing David Bernstein, I often explain that liberty of contract in Buchanan v. Warley was used as a method of fighting segregation. And now, the Supreme Court has endorsed that reading of this (gasp) Lochner-era case.

I did a (brief) search through the Supreme Court database to see how Buchanan has been cited in the past (43 times), but there was nothing nearly this sweeping.

The closest I found was CJ Burger in Palmore v. Sidoti:

This is by no means the first time that acknowledged racial prejudice has been invoked to justify racial classifications. In Buchanan v. Warley, 245 U.S. 60, 38 S.Ct. 16, 62 L.Ed. 149 (1917), for example, *434 this Court invalidated a Kentucky law forbidding Negroes to buy homes in white neighborhoods.

Justice Douglas also limited the scope of the decision in Village of Belle Terre v. Boraas:

If the ordinance segregated one area only for one race, it would immediately be suspect under the reasoning of Buchanan v. Warley, 245 U.S. 60, 38 S.Ct. 16, 62 L.Ed. 149 where the Court invalidated a city ordinance barring a black from acquiring real property in a white residential area by reason of an 1866 Act of Congress, 14 Stat. 27, now 42 U.S.C. s 1982, and an 1870 Act, s 17, 16 Stat. 144, now 42 U.S.C. s 1981, both enforcing the Fourteenth Amendment. 245 U.S., at 78—82, 38 S.Ct. at 19—21. See Jones v. Alfred H. Mayer Co., 392 U.S. 409, 88 S.Ct. 2186, 20 L.Ed.2d 1189.