Walter Williams is an economics professor at George Mason University in Fairfax, Va.

A recent Superman comic book has the hero saying, “I am renouncing my U.S. citizenship” because “truth, justice, and the American way — it’s not enough anymore.”

Though not addressing Superman’s statement, Stanford University Professor and Hoover Institution senior fellow William Damon explains how such a vision could emerge today but not yesteryear. The explanation is found in his article “American Amnesia,” in Defining Ideas, based upon his most recent book, “Failing Liberty 101: How We Are Leaving Young Americans Unprepared for Citizenship in a Free Society.”

The National Assessment of Educational Progress reports only one in four high school seniors scored at least “proficient” in knowledge of U.S. citizenship. Civics and history were American students’ worst subjects.

Professor Damon said that for the past 10 years, his Stanford University research team has interviewed broad cross sections of American youths about U.S. citizenship....