HO CHI MINH CITY, VIETNAM — There’s an exchange in “The Quiet American,” Graham Greene’s novel about the damage American good intentions can cause, that I’ve thought about a lot. It involves Thomas Fowler, the world-weary journalist-narrator of the book, confronting Alden Pyle, an American aid worker with a blinding zeal to stop Communism.

“You and your like are trying to make a war with the help of people who just aren’t interested.”

“They don’t want Communism.”

“They want enough rice. They don’t want to be shot at. They want one day to be much the same as another. They don’t want our white skins around telling them what they want.”

A little more than a half-century after Fowler’s succinct...