When America entered World War II after the bombing of Pearl Harbor, Hollywood was also drafted into the effort — not just to support the cause but also to beat the drums of patriotism and duty. America was going to war and with it, so did the entire country. The men enlisted, the women took jobs in the factories, families tightened their belts and pitched in on civil defense and scrap drives, and the studios were expected not just to reflect the new paradigm, but to set the tone.

It was a sudden, dramatic shift. Before the war, studios were wary of merely hinting at politics in its films, let alone being blatantly partisan. Germany was a major market for American movies and, disgust for Hitler's European aggression and nationalistic bigotry aside, business was business. Only Warner Bros. defied Hitler, giving up the German market to publically support the Hollywood Anti-Nazi League. The studio produced a series of patriotic shorts and features that addressed threats to American democratic ideals throughout the thirties and become the first Hollywood studio to put the word "Nazi" in a film title: 1939’s splashy big screen thriller Confessions of a Nazi Spy.

No longer concerned with German profits (as the ongoing war in Europe made such matters moot), all of the studios soon went on the offensive, producing anti-Nazi dramas and films that, like the aptly-named Howard Hawks’ Sergeant York (1940), seemed designed to prepare Americans for a coming war. Frank Borzage's The Mortal Storm (1940) chronicled the brutal, freedom-crushing rise of German fascism, and Charlie Chaplin contributed a brazen roast of Hitler in The Great Dictator (1940), where he played both a 20th century Napoleon “Adenoid Hynkel” and a look-a-like amnesiac Jewish barber in his first speaking roles and cast Jack Oakie as Italian dictator “Napaloni of Bacteria”.

But it was Alfred Hitchcock who pit good old American pluck and moral outrage against the regime with Foreign Correspondent (1940), his second American production. Newly arrived in Hollywood from Britain, which was taking a beating from German bombings, he had a personal stake in the war that Americans did not, and he had been projecting his concerns onscreen through rousing thrillers like The Lady Vanishes (1938) and The 39 Steps (1935). The latter has the flavor of a Graham Greene-style thriller dropped into a portrait of old Europe about to be upended by war, but the finale, a rousing call to action by our hero in the midst of the bombing of London, pushes the buttons of patriotism.

Foreign Correspondent is an interesting companion piece to Michael Powell's Contraband (1940) – a fleet, energetic British thriller about a no-nonsense Danish Captain (Conrad Veidt) who gets tangled up with Nazi spies in a British port and tosses aside Danish neutrality to join forces with the British against the German menace. Powell and screenwriter Emeric Pressburger turned a wartime propaganda assignment into a witty espionage thriller that makes the most of its nocturnal setting.

After the Japanese attack on Pearl Harbor on December 7, 1941 and German's declaration of war on the U.S. four days later, Hollywood was primed to jump into the war effort with everything at its disposal. Theaters were soon filled with films about American boys training in boot camp or earning their wings – putting aside ego for sacrifice, brotherhood, and teamwork. Many Hollywood stars , like Tyrone Power, the quintessential American who learned humility in A Yank in the R.A.F. and went on to fly as a pilot in the Marine Corps in the Pacific, would also go on to serve. After a few years, those idealistic films gave way to combat dramas like The Story of G.I. Joe (1945), directed by William Wellman (a World War I vet himself), a glamour-less and harsh portrait of war as a never-ending march through mud and blood, war time exhaustion, mental collapse, and the reality of abrupt death.

In his book "Five Came Back," historian Mark Harris tells the story of how Hollywood directors John Ford, Frank Capra, William Wyler, George Stevens, and John Huston went to war to make films for the armed service during World War II. The documentaries they made are among the most revealing documents of the war, and they also brought their experience back home to bear on their craft, and it changed the way they made movies.

Ford won an Oscar for his 1942 documentary short The Battle of Midway (1942). Shot in the heat of battle (they were literally in the line of fire as they documented the Japanese attack) and released in civilian theaters it gave audiences their first glimpse of actual American servicemen engaged in World War II combat. He went on to make a number of films for the military, many of them never seen outside of boot camp. He was called back from active service and sent to Hollywood to make They Were Expendable (1945), a somber fictional drama about the sacrifices made by thousands of American troops in the devastating early Pacific campaign in the months after Pearl Harbor. Like G.I. Joe, it was produced in the waning days of the war when Allied victory was all but assured. So Ford took the opportunity to channel his experiences and observations and remind the American public that victory in the Pacific was achieved at a tremendous human cost.

Director William Wyler made Mrs. Miniver (1942), a stirring portrait of a British family on the home front pulling together in the early days of World War II. Though Wyler shot that drama in Hollywood, he subsequently left to serve his country in Europe, where he made the documentary Memphis Belle: The Story of a Flying Fortress (1944). Wyler's depiction of a B-17 bomber crew on its final mission (actually shot over multiple missions, all of them with Wyler accompanying them in combat) showed audiences a crew working together under fire, but just as important, it gave audiences access to the boys behind the uniforms. It's surely no coincidence that a B-17 bomber is the transport plane that carries the three returning veterans in Wyler's 1946 drama The Best Years of Our Lives, which shows men adjusting to civilian life after years of combat. The film ends with Dana Andrews' character, a former pilot, wandering through a field of decommissioned bombers. Though Wyler didn't fight, his experiences in the thick of it gave him the insight and compassion to turn his "statement" about the experience of the returning veteran into his most soulful drama.

Frank Capra had the biggest challenge: taking on the outmoded Army Signal Corps, which had been in charge of filmmaking within the services since 1929. The unit was responsible for training films and field reports and the results were dull and droning documents. Capra was determined to produce films that entertained and engaged the young and often uneducated soldiers while transmitting important information. In addition to training films, he was charged with making documentaries for new recruits about the origins of the war, profiles of America's enemies and allies, and a newsreel film magazine for the soldiers which included the witty cartoon series "Private Snafu," featuring the talents of Warner Bros. directors and writer Theodor Geisel.

Working with director Anatole Litvak, Capra won an Oscar for Prelude to War (1942), the first of seven films in the "Why We Fight" series, which took on the history of the war and, with great ingenuity, overcame the tight budgetary restrictions by using confiscated German propaganda films against the Nazis. Capra went on to make The Nazis Strike (1943), Divide and Conquer (1943), The Battle of Britain (1943), The Battle of Russia (1943), The Battle of China (1944), and War Comes to America (1945), the final film in the series. Though produced for the enlisted men, some of these also played for civilian audiences. The first film Capra made upon returning home was It's a Wonderful Life (1946), which takes a harrowing detour into a dark reality unlike anything he had put on screen before. Having shown soldiers why we fight, Capra seemed determined to remind civilians why we live.

John Huston was the youngest of the five directors profiled in Harris' book. A longtime screenwriter, Huston had only directed two features before reporting for duty. In many ways, he was the maverick of the group. His short documentary San Pietro (1945) documents the battle to take a small Italian village from the occupying German forces. Huston actually arrived after the battle was already over, so he recreated it in a manner so convincing that for years audiences believed it to be genuine war reportage. It remains one of the most devastating onscreen portrayas of war, a grueling record of destruction and loss of life in a single battle. Let There Be Light (1946), his final documentary for the military, turned the cameras on Mason General Hospital on Long Island, a racially integrated psychiatric hospital where soldiers suffered from and underwent treatment for psychological rather than physical injuries. It was the first film to explore "psychoneurotic" damage, known better today as post-traumatic stress disorder or PTSD, and it groundbreakingly showed black and white soldiers working in group therapy sessions together. The military prevented public screenings of the film for 35 years. Was it because it revealed the vulnerability of humans affected by the psychological trauma of war? Or was it because it showed that integrated military life was not only possible, but productive, at a time when the military was segregated?

Interestingly enough, Hitchcock contributed further to the war effort with two propaganda pieces, both in French, for the British Ministry of Information. The short films Bon Voyage (1944) and Aventure Malgache or Madagascar Landing (1944) are not documentaries but dramatic pieces, miniature espionage thrillers that unfold in flashback. The first features a British pilot recounting his escape from a POW camp with the help of the French Resistance and then rewinds to offer a different perspective, Rashomon style. The second is a tale of the Resistance battling Vichy collaborators in French Madagascar as told by a French actor to his fellow performers. Both films are wily little pieces that defy the dictates of propaganda as they play with storytelling and puncture the heroism of its characters, which is probably why they weren't shown for almost fifty years after their making. They are minor Hitchcock works, true, but they each have their charms, not least of which is a highly-crafted sense of suspense and mood on a budget.