David Boaz, a Leading Voice of Libertarianism, Dies at 70

David Boaz, an apostle of “reasonable, radical libertarianism” who argued that Americans are entitled to pursue life, liberty and happiness without government meddling in their bedrooms or boardrooms or with their cannabis, died on Friday at his home in Arlington, Va. He was 70.

The cause was complications of esophageal cancer, his longtime partner, Steve Miller, said.

Mr. Boaz encapsulated libertarianism, the philosophy that prioritizes individual freedom over government overreach, with characteristic perspicuity:

“You learn the essence of libertarianism in kindergarten,” he wrote in “Libertarianism: A Primer,” a 1997 book that was updated and rereleased in 2015 as “The Libertarian Mind: A Manifesto for Freedom.” “Don’t hit other people, don’t take their stuff, and keep your promises.”

As executive vice president of the Cato Institute, the Washington-based libertarian think tank, since 1989, Mr. Boaz was a frequent contributor to its magazine, Reason. He also wrote opinion essays for The New York Times and other publications, advancing a philosophy that had been embraced for centuries by thinkers like John Locke, Adam Smith, Thomas Jefferson, Ayn Rand and Milton Friedman, but whose practical application posed challenges to some potential disciples.

Summing up his holistic view of individual liberty, Mr. Boaz told The Times in 1984, “I don’t think it’s any of the government’s business to protect people from themselves, whether it’s seatbelts, cyclamates or marijuana.”

Nor, he argued, did it make any sense to deny gay people legal equality. Government benefits, for example, should not be withheld from same-sex partners in stable relationships, he said, when children of single-parent families or of unmarried heterosexual