From a May 24 Wall Street Journal editorial:

A Senate campaign is not a libertarian seminar, a lesson that Kentucky Republican Rand Paul has learned the hard way since his primary victory on Tuesday. He has now renounced the doubts he expressed last week about some parts of the Civil Rights Act of 1964 and has declared the matter closed. But before we move on, it's important to understand why Mr. Paul was wrong even on his own libertarian terms.

In his acceptance remarks on Tuesday night, Mr. Paul sounded mainstream conservative themes on spending, taxes and the reckless expansion of state power. But in his first brush with national scrutiny, the eye doctor let himself be drawn into a debate over the landmark 46-year-old law. Some conservatives want to blame liberal journalists for asking the questions, but Mr. Paul agreed to appear on MSNBC, and such queries were predictable given the liberal stereotype that all conservatives are secretly racists.

[...]

Even if Mr. Paul was speaking out of a principled belief in the rights of voluntary association, he was wrong on the Constitutional and historic merits. The Civil Rights Act of 1964 -- and its companion laws, such as the Voting Rights Act of 1965 -- were designed to address abuses of state and local government power. The Jim Crow laws that sprang up in the South after Reconstruction and prevailed for nearly a century were not merely the result of voluntary association. Discrimination -- public and private -- was enforced by police power and often by violence.

In parts of the mid-20th-century South, black men were lynched, fire hoses and vicious dogs were turned on children, and churches were bombed with worshippers inside. By some accounts, two-thirds of the Birmingham, Alabama, police force in the early 1960s belonged to the Ku Klux Klan. State and local government officials simply refused to acknowledge the civil rights of blacks and had no intention of doing so unless outside power was brought to bear.

The federal laws of that era were necessary and legal interventions to remedy the unconstitutional infringement on individual rights by state and local governments.

Previously:

WSJ's Gigot: Rand Paul “is wrong about the Civil Rights Act”