Well, in a week in which President Donald J. Trump decertified the Iran nuclear deal, eliminated subsidies for insurance companies that underwrite poorer Obamacare enrollees and warned Puerto Rico that the federal government can’t buck it up forever, the American withdrawal from UNESCO may seem like small potatoes. But as a longtime cultural writer I noted it with a heavy heart.

As with these other issues, the United Nations Educational, Scientific and Cultural Organization is more complex than it seems. The U.S. helped found it after World War II, but in recent decades has had an off-and-on again relationship with the organization, which is well-known for its significant World Heritage Sites list. ...