‘Churchill’s American Network: Winston Churchill and the Forging of the Special Relationship’
By Cita Stelzer
Foreword by Randolph Churchill
Pegasus Books, 336 pages

‘Churchill’s D-Day: The British Bulldog’s Fateful Hours During the Normandy Invasion’
By Allen Packwood and General Sir Richard Dannatt
Diversion Books, 352 pages

Winston Churchill’s great-grandson says it in a sentence: “What is often forgotten is that Churchill was able to save the world from the scourge of Nazism in part because he had the foresight to create a network of support for Britain and the English-speaking peoples long before anyone had expected such support would be needed.”

The adventuresome Churchill is worthy of an 18th-century picaresque novel, and Cita Stelzer obliges with chapter titles such as “Building the American Network, Link by Link, Wherein Churchill meets and woos the ‘influencers’ he needs for his network”; “1929: Westward Ho, Nibbling Some Grass, the Troupe Goes to Hollywood, Wherein Churchill Experiences the vastness of America from sea to shining sea”; “1929: Winston in Tinseltown, with Hearst at His Castle in San Simeon, Wherein Churchill enjoys a winery, a forest, the Hollywood scene, and a media baron.”

Then, Churchill heads back east to Chicago, and he learns a lesson on Wall Street as well. So it goes through the 1930s with Churchill’s rendezvous with history: “1932-1941: FDR, Luce, and Churchill’s Newport Take on Isolationists, Wherein Time’s Man of the Year and his network, with Roosevelt and Luce, battle the isolationists.”

Not that Churchill’s frequent visits to America were just about acquiring allies. As Ms. Stelzer notes, the man was in “constant need of money,” and as with many of his British contemporaries, the lecture circuit supplied handsome fees and opportunities to plug his books. Churchill as platform performer cultivated audiences, reporters, and their employers to fashion a heroic and entertaining persona.

Biographers often brag about their access to new or neglected archives, but Ms. Stelzer consulted hundreds of press reports to convey the content and style of Churchill’s performances. Churchill had his share of protestors: the Irish and Indians who showed up to taunt him. He treated them with aplomb in quips widely reported in the press. In short, the influencers and the influenced became part of Churchill’s American network.

The highly credentialed director of the Churchill Archives Centre, Allen Packwood, and a former chief of the British General Staff, General Sir Richard Dannatt, provide a riveting account of the D-Day landings, cross-cutting with Churchill’s deft handling of the momentous invasion that confirms Ms. Stelzer’s depiction of a media genius decades in the making.

When Churchill entered the House of Commons to announce the D-Day landings, the news had already been broadcast on radio. Mr. Packwood and General Dannatt quote MP Harold Nicolson, who watched the prime minister enter “white as a sheet.” Nicolson dreaded a report of some “terrible disaster.” To a hushed House, Churchill began by praising the Allied effort to liberate Rome and the Anzio landings.

Why did Churchill begin this way? The biographers suggest it was an “element of theater” to delay the electrifying news but also his way of paying tribute to the British-led operations in Italy. They miss a good point here: He led with Rome’s liberation because of its symbolic importance. A man who was mindful of the verdict of history wanted to begin with declaring that all roads to Rome, and the center of Western Civilization, had been restored.

D-Day, Churchill understood, had just begun, and other than reciting the facts — the “immense armada of upwards of 4,000 ships, together with several thousand small craft,” the successful airborne landings, with 11,000 aircraft in reserve to be used as needed — he declared that all was going “according to plan. And what a plan! This vast operation is undoubtedly the most complicated and difficult that has ever occurred.”

Churchill spelled out the difficulties of dealing with “tides, wind, wave, visibility,” but declared that “complete unity prevailed” under the “brotherhood of arms” led by the supreme commander, General Eisenhower, and the leader of the expeditionary force, General Montgomery. So it was that Churchill was able to segue to the present  from history — even as history was being made.

How history is spoken matters, and both of these books show why no one was better at speaking it than Churchill.

Mr. Rollyson’s work in progress is “Making the American Presidency: How Biographers Shape History.”