This is precisely the case Barry Goldwater, the leader of the Republicans’ conservative wing, made on the Senate floor just before the final vote on the Civil Rights Act. “I am unalterably opposed to discrimination of any sort,” Mr. Goldwater said, even as he attacked provisions of the bill that “would embark the Federal Government on a regulatory course of action with regard to private enterprise and in the area of so-called ‘public accommodations’ and in the area of employment.”

Public accommodations included gas station rest rooms, drinking fountains, lunch counters, hotels, movie houses and sports arenas. It is hard to imagine a candidate today making the case that discrimination in such places should be allowed. Indeed Mr. Paul has said he favors the “public accommodations” provision. But in advancing the autonomy of private businesses, he is reviving libertarian thought in its peak period. In his 1962 book “Capitalism and Freedom,” Milton Friedman, the right’s most influential economist, equated the Fair Employment Practices Commissions — created to prevent workplace discrimination — with “the Hitler Nuremberg laws.” But he also applied the comparison to “the Southern states imposing special disabilities upon Negroes.” In other words, he recognized that Jim Crow was itself a form of intrusive government, only enacted at the state level.

This points to the bind Mr. Paul is in. However attractive it may be just now to depict all political conflict as a neatly bifurcated either/or, with the heroic individual pitted against the faceless federal Leviathan, the truth is that legislative battles over civil rights laws were waged within government, and between competing incarnations of it, federal vs. state. Passage of the Civil Rights Act, as Senator Lindsey Graham of South Carolina observed last week, hinged on the Interstate Commerce Clause, which “was properly used by the courts and the Congress.”

The reasoning was clear: since the federal government built the highways that goods were shipped on and created tax codes favorable to businesses, it had jurisdiction over how businesses operated. Even Mr. Friedman acknowledged that racial discrimination could not be interpreted in the exclusive terms of individual choice. “When the owner of the store hires white clerks in preference to Negroes in the absence of the law, he may simply be transmitting the tastes of the community,” he wrote.

But he stopped short of noting the obvious, that in such instances the white community’s “taste” had made it the enemy of individual African-Americans who were forbidden to sit at a luncheonette or take their children into a Woolworth’s rest room.

Mr. Paul has tangled himself up in a similar contradiction. His championing of private businesses, ignoring the rights of just about everyone else, places him on the wrong side of history, just like the first opponents of the Civil Rights Act. One fierce opponent of civil rights legislation, William F. Buckley Jr., admitted as much. “I once believed we could evolve our way up from Jim Crow,” Mr. Buckley said in 2004. “I was wrong: federal intervention was necessary.”