‘Louis, I think this is the beginning of a beautiful friendship.” Few moments in cinema history are more famous than these words spoken by Rick Blaine (Humphrey Bogart), the owner of the seedy Rick’s bar, to the local French police chief, Louis Renault (Claude Rains), at the end of the 1942 film “Casablanca.” But probably few people remember today that this most beloved of Hollywood romantic dramas carried contemporary political messages.

In 1942, Morocco was part of the French North African territories controlled by the Vichy government of Marshal Philippe Pétain. Established after France’s defeat in World War II in 1940, Pétain’s government was pursuing a policy of collaboration with Nazi Germany. In the film, Louis has to obey the orders of the Germans. Only in the last scene does he suddenly discover a patriotic backbone. He allows the beautiful Ilsa (Ingrid Bergman) to escape with her husband, a leader of the European resistance. Rick lets political conviction trump his love for Ilsa. He watches Ilsa and her husband board the aircraft that will take them to freedom and shoots the German officer who tries to prevent them. Louis, instead of denouncing Rick, orders his men to “round up the usual suspects.” Tossing a bottle of Vichy water into a wastepaper basket, he walks off into the night with Rick to join the anti-Vichy French forces of Gen. Charles de Gaulle.

American viewers of the film would have grasped only too well that the offstage villain is Pétain and the offstage hero de Gaulle — but they would also have known that their own government had for the past two years sedulously cultivated Pétain’s Vichy regime and contemptuously ostracized de Gaulle, who opposed it from London. “Casablanca” tapped into the huge unpopularity of this policy among the American public. Secretary of State Cordell Hull was so embarrassed by criticisms of this policy that he offered unfettered access to State Department archives to the Harvard historian William Langer so that Langer could write a defense. While not a complete whitewash, Langer’s book, “Our Vichy Gamble,” was broadly apologetic; one reviewer remarked that it would have been better titled “Our Vichy Fumble.”

Now this controversial period of U.S. policy is revisited by the American diplomatic historian Michael S. Neiberg. One message of his meticulously researched but extremely readable book, “When France Fell: The Vichy Crisis and the Fate of the Anglo-American Alliance,” is that this was no minor side story. It was central to the history of World War II, even if it was later overshadowed in American memory by the war in the Pacific. France’s fall in 1940 alarmed the Roosevelt administration just as much as the attack on Pearl Harbor 18 months later. Secretary of War Henry Stimson later called it “the most shocking single event of the war.” What if the huge French fleet — described by Hull as a “cocked gun waiting for Germany to shoot at us” — fell into German hands? What if the Germans got access to French territories in the Caribbean? What if the Germans were allowed to use the French base at the port of Dakar, jutting out dangerously into the Atlantic? In short, the French defeat meant that the entire Western Hemisphere was dangerously exposed.

The American administration desperately cobbled together a response to this threat. Its solution was to reach out to the Vichy regime. Although the politician and former French prime minister Pierre Laval was committed to collaboration, other figures at Vichy, such as Gen. Maxime Weygand, were believed to be more favorable to the Allies. Pétain’s true beliefs remained mysterious. President Franklin Roosevelt sent his close friend Adm. William Leahy to be American ambassador to Vichy. To show how much this mattered, Leahy arrived in January 1941 with the full pomp usually afforded only to a president.

Another theme of Neiberg’s excellent book is that, although today we celebrate the close wartime relationship between Roosevelt and Winston Churchill, the two leaders were profoundly divided on their approach to France. While Roosevelt gambled on Pétain, the British supported de Gaulle, who had arrived in London after the fall of France. Churchill often found de Gaulle difficult to deal with, but Britain never reneged on its support for him — to the fury of Hull.

The crunch moment for the U.S. policy of cultivating Vichy came in November 1942 when Allied troops landed in North Africa. The hope was that the Vichy leaders on the ground would rally to the Allies. In fact, Vichy troops resisted as long as they could: 1,469 people died (including 530 American troops). When further resistance proved impossible, Adm. Jean-François Darlan, the most senior Vichy leader present in North Africa, defied Pétain in France and signed an armistice with the Americans. But he did this only after the Germans were allowed to land in Tunisia, from where it took another five months for the Allies to dislodge them.

Even so, the Americans agreed to install Darlan in North Africa. This “Darlan deal” with a notoriously right-wing, antisemitic former collaborator caused international outrage. The Americans were probably relieved when Darlan was assassinated at the end of December 1942. Still suspicious of de Gaulle, Roosevelt found another candidate to take charge in North Africa in the form of Gen. Henri Giraud. Giraud was reactionary and inept, but at least he was not de Gaulle. The British became ever more exasperated, but right up until D-Day Roosevelt did all he could to sideline de Gaulle.

Neiberg tells us that he started with the hypothesis that U.S. policy might have been justified in terms of necessary pragmatism. States sometimes have to get their hands dirty in a wider cause. He concludes, however, that in the end, the policy produced nothing and was “based as much on fear, confusion, and misguided faith as anything else.” Again and again his judgments are excoriating: “The United States had no positive influence on Vichy leaders.” Even Leahy wrote to Roosevelt that he could not “point to any useful accomplishment that we have made since my arrival six months ago.”

Many of the same events are covered in Martin Dugard’s “Taking Paris: The Epic Battle for the City of Lights.” But in all other respects his book could not be more different from Neiberg’s. It is a work of popular history by a best-selling author who tells us that, writing during the coronavirus lockdown, he could not visit archives, museums or historical sites. His research, mainly carried out on the Internet, offers no new archival discoveries. Instead his ambition is to tell a gripping story. In this he succeeds triumphantly. One reads his narrative, mostly in the present tense, as if watching a film. His story is divided into 75 short chapters that focus on the events of a single day or even a few hours.

The first chapter begins at 1600 hours on May 13, 1940, as Gen. Erwin Rommel, commander of Germany’s 7th Panzer Division, is preparing to take his first tanks across the supposedly almost impassable Meuse River. Once the river is crossed the road to Paris lies open. The final chapter, Aug. 24, 1944, late afternoon, culminates with the liberation of Paris and the arrival of de Gaulle.

Between these two moments, the author takes us from Paris to Casablanca (the real one, where Roosevelt and Churchill attempted to broker a deal between “their” two generals, Giraud and de Gaulle); from the beaches of Anzio to the cabinet rooms in London; from the Western Desert of Egypt to Burbank, Calif. (and the studio where “Casablanca” was made). There are many familiar figures — Roosevelt, Rommel, Gen. George S. Patton, Gen. Dwight Eisenhower — but also less-famous ones. For example, one chapter introduces us to Jacques Bonsergent, the first Frenchman to be executed by the Germans in occupied Paris because he was unfortunate enough to come across a drunken German soldier. In another chapter we meet Gen. Marie-Pierre Koenig, the Free French commander who heroically held off Rommel’s forces for 10 days at the Battle of Bir Hakeim in the Western Desert, preparing the way for the later British victory of El Alamein. Perhaps the most extraordinary character in the story is Virginia Hall, an American woman who worked as a spy for the British in occupied France, setting up an important resistance network. Hall, who had lost a leg in a hunting accident, had a prothesis she called Cuthbert.

Dugard has real narrative gifts. His account of the moments leading up to the assassination of a German naval officer, Alfons Moser, by a communist resister on the platform of the French subway (Aug. 21, 1941, 8 a.m.) reads like a novel. I have read innumerable books on the fall of France, and even written one myself, but never has any writer conveyed more vividly to me what it was like to be in a French tank for the four members of the crew. Occasionally, one wonders if all the little details he provides us are necessary. Does it really add much to know that Darlan’s assassin used a Ruby 7.65 pistol or that the plane taking de Gaulle to London was a de Havilland Dragon Rapide? (In fact, some writers claim it was actually a de Havilland Flamingo). But that is the style of this kind of historical writing — as is the slightly breathless tone — and there are always military buffs who love this kind of detail.

These two very different books will remind American audiences just how much France once mattered and what an extraordinary pull Paris used to exert on the imagination of the world (“We’ll always have Paris,” Rick reminds Ilsa). This may no longer be true, but the story told here left a legacy. De Gaulle had a long memory, and his contentious relationship with America in the 1960s — he took France out of NATO — has its roots in the disastrous choices made by the Roosevelt administration. Perhaps there is also a contemporary message for British Brexiteers who like to romanticize the “special relationship” with the United States. It was never that special, even in its heyday.

When France Fell

The Vichy Crisis and the Fate of the Anglo-American Alliance

By Michael S. Neiberg

Harvard.
312 pp. $29.95

Taking Paris

The Epic Battle for the City of Lights

By Martin Dugard

Dutton Caliber.
385 pp. $30