In the 1930s, antiwar feeling was widespread. In 1936, some 500,000 students, almost half of the undergraduates in the United States, participated in a strike against war and compulsory ROTC. During the decade, pacifism may have surpassed the Depression as the dominant social issue among American liberal Protestants. "I am a pacifist," President Franklin Roosevelt declared in 1940.

With Japan's attack on Pearl Harbor, isolationism and pacifism went out of fashion. Still, according to Daniel Akst, as it was pushed to the margins, pacifism became countercultural. Its much smaller "remnant" felt "liberated to move in new directions and develop new tactics."

In "War by Other Means," Akst focuses on four activists — David Dellinger, Bayard Rustin, Dorothy Day and Dwight MacDonald — to tell the little-known story of pacifist activism during World War II.

Akst attempts a delicate balancing act. He celebrates these individuals (and many of their colleagues) for their idealism, integrity, courage and influence on the American Left in the ensuing decades. And he dismisses pacifism for offering a mushy "hodgepodge of utopian ideas and crude absolutism" to counter the threats posed by the Nazis, including genocide.

Akst provides fascinating biographical sketches of his protagonists. Dellinger, we learn, was born to an affluent family, studied economics at Yale, spent a year at Oxford, visited Germany, and returned to New Haven, where he worked for the Yale Christian Association. Radicalized by the Depression and the New Testament, he turned away from basic comforts, rode the rails, and slept alongside hoboes.

A student at Union Theological Seminary, Dellinger refused to register for the draft, was sent to Danbury prison, where he organized work stoppages and hunger strikes to protest arbitrary punishments, segregation, censorship of mail and restrictions on reading. And, Akst point out, he developed a sense of invulnerability that got him through difficult challenges, including Vietnam-era prosecution as a member of the Chicago Seven.

Bayard Rustin's homosexuality, Akst reminds us, meant that he was confined to the background of the civil rights movement and robbed of his rightful place in the pantheon, alongside A. Philip Randolph, James Farmer, John Lewis, and Martin Luther King Jr.

Mistaken, "of course," Akst writes, about U.S. participation in World War II, for which they offered no realistic alternative, pacifists moved from conscientious objection to a substantially more wide-ranging reform agenda.

They pressed for change in prisons and mental hospitals; protested the forced evacuation to Japanese Americans concentration camps; demanded that the Roosevelt administration do more to save European Jews. They founded the Congress for Racial Equality and helped make nonviolent mass protest a foundational strategy for the civil rights movement. They taught Americans to be wary of authority, consolidation and dehumanization.

"Easy to dismiss as a tiny and quixotic band of outliers," Akst concludes, pacifists helped teach us, along with Hannah Arendt, that even when it's necessary to fight, "those who choose the lesser evil, forget very quickly that they chose evil."

Glenn C. Altschuler is the Thomas and Dorothy Litwin Professor of American Studies at Cornell University.

War by Other Means: The Pacifists of the Greatest Generation Who Revolutionized Resistance

By: Daniel Akst.

Publisher: Melville House, 368 pages, $28.99.