Purity May Be Rand Paul's Greatest Strength. But It's Also His Greatest Weakness.

Rand Paul is a purist.

If his qualifications for that title were ever in doubt, they're not anymore. Less than 36 hours after Kentucky Republicans chose Paul as their 2010 U.S. Senate nominee, the Bowling Green ophthalmologist has now plunged head first into a scalding vat of political hot water by declaring that the 1964 Civil Rights Act should not have prohibited private business owners from discriminating against potential customers because of the color of their skin.

The remarks make Paul sound like a racist, as my fellow Gaggler Howard Fineman points out, and that perception will certainly be a problem as he battles Democrat Jack Conway in the Bluegrass State's general election. But Paul's real problem here—the basic truth that this episode has revealed—isn't racism. It's the fact that his greatest strength—the authentic, unadulterated ideological purity that endeared him to Kentucky's Tea Party types in the first place—is also his greatest weakness.

Being pure means believing that a single principle is the answer to every question. In Paul's case, that principle is libertarianism: the idea that human liberty is best preserved by limiting government's scope to the barest minimum. As Paul put it in a recent interview, it's "about believing in freedom."

But by opposing the part of the Civil Rights Act that stopped private business from discriminating against African-Americans, Paul is saying that "believing in freedom" is about nothing more than making sure the government doesn't prevent people from doing whatever they want to do. The trouble is, government isn't the only force that can restrict our freedoms. Other people can make us less free as well—like, for example, when they refuse to serve us food or sell us a house simply because we're black.

And that's the most disturbing thing about Paul's newly revealed position on civil rights. He is so in thrall to his own purity and so determined to be absolutely consistent that he fails to recognize a rather obvious fact: by adhering so slavishly to the letter of the libertarian law, he is plainly violating its spirit. Which freedom was more deserving of protection in Selma, Ala., circa 1964? The freedom of diner owners to treat African-Americans like second-class citizens? Or the freedom of African-Americans to eat wherever they could afford?

Principles like Paul's can be admirable. There is plenty to like about practical libertarianism. But purity isn't more important than reality, and ideology is only as good as the outcomes it produces. Going forward, the voters of Kentucky will have to decide which outcome they prefer: making a statement or making the country stronger. America may have been a purer place without the Civil Rights Act. But it also would've been a whole lot less free.