“It is seldom,†David Hume wrote, “that liberty of any kind is lost all at once.†That admonitory sentence furnishes one of the epigraphs for Friedrich Hayek’s The Road to Serfdom, first published in 1943. How is freedom faring in the United States today? Peter Robinson, a scholar at the Hoover Institution at Stanford, provided a melancholy précis in “The Loss of Individual Liberty,†a column that appeared in Forbes last month. Mr. Robinson recalled a dinner he shared with Milton Friedman several years ago. He complimented the venerable economist on his role in transforming the intellectual landscape, especially in...