Justice Anthony Kennedy has been called the most libertarian member of the Supreme Court (though Ilya Shapiro finds his libertarianism "faint-hearted"). So maybe it's no surprise that in the Lawrence (2003), Windsor (2013), and Obergefell (today!) cases, Kennedy wrote a majority decision finding that gay people had rights to liberty and equal protection of the law.
As I note in The Libertarian Mind and in an article just posted at the venerable gay magazine The Advocate, libertarians and their classical liberal forebears have been ahead of the curve on gay rights for more than two centuries:
As the Supreme Court prepares for a possibly historic ruling, most of the country now supports gay marriage. Libertarians were there first. Indeed John Podesta, a top adviser to Bill Clinton, Barack Obama, and Hillary Clinton and founder of the Center for American Progress, noted in 2011 that you probably had to have been a libertarian to have supported gay marriage 15 years earlier.
Just seven years ago, in the 2008 presidential campaign, Barack Obama, Joe Biden, and Hillary Clinton all opposed gay marriage. The Libertarian Party endorsed gay rights with its first platform in 1972 — the same year the Democratic nominee for vice president referred to “queers” in a Chicago speech. In 1976 the Libertarian Party issued a pamphlet calling for an end to antigay laws and endorsing full marriage rights.
That’s no surprise, of course. Libertarians believe in individual rights for all people and equality before the law. Of course they recognized the rights of gay people before socialists, conservatives, or big-government liberals.
In the article, and more so in the book, I talked about some of the history of classical liberal-libertarian thinking on gay rights in earlier centuries, perhaps beginning with the pioneering criminologist and reformer Cesare Beccaria in 1764.
The Declaration of Independence promised life, liberty, and the pursuit of happiness to Americans. Of course, not everybody enjoyed those rights at first. But eventually those ideas took root and led to the abolition of slavery and later to civil rights and women’s rights. It took even longer for people to take seriously the idea of homosexual activity as a matter of personal freedom and to recognize gays and lesbians as a group deserving of rights.
It was the classical liberals, the ancestors of libertarians, who first came to that recognition. From Montesquieu and Adam Smith in the 18th century to the Nobel Prize–winning economist F.A. Hayek in 1960, it was libertarians who insisted that (in Hayek’s words) “private practice among adults, however abhorrent it may be to the majority, is not a proper subject for coercive action for a state whose object is to minimize coercion.”