It was the Year Before. The year before Ted Williams and Joe DiMaggio would light up the baseball world with the numbers .406 and 56. The year before the Jeep was invented and the Manhattan Project was started, the year before Mount Rushmore was completed, the year before Joan Baez was born, the year before 2,402 victims of the attack on Pearl Harbor would die.
But 1940 was more than the Year Before. It was a time and era all its own: the Luftwaffe bombing assault on London, the assassination of Trotsky, the discovery of Stone Age carvings in a cave in France, the appearance of nylons on the market. The Bears beat the Redskins, 73-0, in the NFL championship game. Byron Nelson won the PGA Championship.
And it was the year Franklin Delano Roosevelt won an unprecedented third term in the White House. It is this presidential drama that is the centerpiece of Susan Dunn's volume with the pithy, strangely evocative title of "1940.'' The book is a meticulous reconstruction of several battles: the one between FDR and Wendell Willkie, naturally, but also the struggle between those who believed in isolationism and those who believed in engagement. And the clash between those who believed the best answer to Hitler and Mussolini was appeasement and those who believed instead in forceful response and rearmament.
Few years—1941, of course, and surely 1776 and 1861, and maybe 1968 and 2001—offer so rich an American canvas, and Ms. Dunn, a prolific historian at Williams College, uses it to paint a brilliant portrait of an America in transition, not only between war and peace but also between a country content to stick to its knitting and one that would soon sew together alliances and assume obligations across the globe.
Ms. Dunn's story begins with Japan at war in China, Germany on the move through Europe, and Americans registering for the draft and taking jobs in the growing defense industry. From the start it is clear that this was a time of transformation—and crisis.
The year was dominated by two questions whose answers would change the country. Would Roosevelt run for the third term that none of his predecessors dared undertake? And would the United States, possessed of the world's 18th biggest army, only slightly bigger than Bulgaria's, be drawn into the war that was darkening the globe?
On the war, FDR took what you might call a lean-in position, observing in his State of the Union address that there was a "vast difference'' between "keeping out of war and pretending that this war is none of our business.'' On the question of the third term, Hitler all but resolved Roosevelt's conundrum, and the nation's.
One of the long shadows of the year (and, it turns out, of the year ahead, too) was cast by Charles Lindbergh: hero of Le Bourget, seatmate of Hitler at the 1936 Olympics, "intensely pleased''—his words—by the Nazi experience. FDR thought him a Nazi, but perhaps he was simply shallow and narrow. Lindbergh, whose relationship with FDR also is a principal theme of another book this season, Lynne Olson's "Those Angry Days," stands out for his ignorance but not for his isolationism, a creed embraced by, among many others, the old Herbert Hoover and the young Gerald Ford, the reigning president of the University of Chicago (Robert Maynard Hutchins), and the future president of Yale (Kingman Brewster), all suffering from what the playwright Robert Sherwood described as an "isolationist fetish.'' Their brand of isolationism was a mixture of pacifism and defeatism in the face of fascism and totalitarianism, with a few of them throwing in a sprinkle of anti-Semitism as seasoning.
Then there was Willkie himself, the chairman of the Commonwealth and Southern Utilities Corp. He won the Republican nomination by beating out Thomas Dewey (fabled gangster-buster), Robert Taft (first in his class at both Yale and Harvard Law and a noted isolationist), Arthur Vandenberg ("abstruse,'' she tells us, "with his overly subtle distinction between isolationism and insulationism''), and Herbert Hoover ("out of touch'').
A onetime Democrat and longtime internationalist, Willkie battled the Ku Klux Klan, made a fortune on Wall Street, and made some women, and a handful of powerful publishers, swoon. "I am utterly devoid, I believe, of political ambition,'' he said, which of course positioned him perfectly to attain his ambition, the Republican presidential nomination.
Willkie's appeal was on the economic side, offering a humane alternative to the New Deal he reviled, one concentrating on competition and free markets. "The true liberal,'' he said, "is as much opposed to excessive concentration of power in the hands of government as . . . in the hands of business.'' This was a challenge both to the New Dealers and to the Republican Old Guard. At the Republican National Convention he was, as Ms. Dunn puts it, "a colorful maverick in a sea of gray.''
Willkie never quite fit in the party that nominated him, referring in his acceptance speech to "you Republicans'' and prompting Lindbergh to describe him as a "problem child.'' If politics were a matter of logic, Willkie's nomination would have removed the rationale for FDR's third term, but the long history of American politics is a treatise against logic, which is why books like Ms. Dunn's—primarily a colorful account of that most colorful American art form, the presidential campaign, with its banners, bands, bunting and bunkum—are so captivating.
For his part, Roosevelt—no revisionism here, just the customary heroic but enigmatic FDR—encouraged multiple worthies to become presidential candidates. As a result, no single alternative emerged, and the party that had stoutly resisted a third term for Grover Cleveland gladly offered one to Franklin Roosevelt. "It's been grand fun, hasn't it!'' the president said to Sherwood and adviser Sam Rosenman the Sunday night before the election, and it was.
But there would be little in the way of grand fun for Roosevelt or anyone else in the years to come—even in the year to come. FDR had won every large city except Cincinnati, but the office he continued to occupy soon took on the burden of preserving American democracy, American freedoms and American independence. The man whom Carl Sandburg on the night before the election had described as "a not perfect man and yet more precious than fine gold'' faced rearmament, Lend-Lease, continued struggles against isolationists and appeasers, and, after Pearl Harbor, a two-front war against formidable foes whose leaders possessed more personal power, and for a time more firepower, than he.
After the election Willkie became a sturdy supporter of engagement, an effective emissary for FDR and a powerful pugilist against Lindbergh, whose attacks only escalated. The victor, and the country he had sought to lead through the woes of war, thus benefited from the broad-mindedness and personal generosity of the vanquished. "For the good of the country and the survival of democracy around the world,'' Ms. Dunn writes, "the former rivals sought to work together and probably came to respect each other.'' Few years turn out to be as perilous as 1940, or as portentous.
—Mr. Shribman is executive editor of the Pittsburgh Post-Gazette and the Pittsburgh Press.
A version of this article appeared June 15, 2013, on page C5 in the U.S. edition of The Wall Street Journal, with the headline: The Year of Hesitation.