America’s home front effort included recruiting for the military, participating in scrap drives, paying income taxes, buying war bonds, using rationing coupons, planting Victory gardens, encouraging sanitation, volunteering for civil defense work, increasing public morale, and participating in industrial retooling and production. The Hollywood studios that were making cartoons at the beginning of the war were quickly drafted into turning their art to the war effort, to mobilize the American public. Cartoons were just one part of a propaganda effort, which also included the production and distribution of feature films, posters, war-themed commercial radio, newspaper and magazine advertising, the organization of celebrity tours and war bond drives, the establishment of censorship offices, and the formulation and distribution of a barrage of information and directives from various government officials and agencies.

Leon Schlesinger Productions produced popular cartoons featuring Daffy Duck and Bugs Bunny for Warner Brothers Studios, many of which had war themes, such as “The Ducktators” (1942), “Confusions of a Nutzy Spy” (1943), “The Fifth Column Mouse” (1943), “Tokio Jokio” (1943), “Daffy—The Commando” (1943), “Falling Hare” (1943), and “Draftee Daffy” (1945).

At least two of these Warner Brothers’ cartoons focused on home front activities and might be the cartoon you’re thinking of: “Scrap Happy Daffy” (1943), and ”Wacky Blackout” (1942).

Walt Disney also produced many war-themed cartoons with Mickey, Donald, Goofy and the rest of the gang, some of which were focused on the home front, such as “Out of the Frying Pan into The Firing Line” (1942), and ”Food Will Win the War” (1942).

A collection of short cartoons and movies from the Disney Studio during World War II, which includes many intended for the home front, was released (for purchase) in 2004 as a 2-disc DVD, “On the Front Lines,” in the series “Walt Disney Treasures.” This collection includes such titles as “Donald Gets Drafted” (1942), “Private Pluto” (1943), “Home Defense” (1943), “All Together” (1942), “Defense Against Invasion” (1943), and “Cleanliness Brings Health” (1945), as well as many others. The collection also includes Disney’s 1943 animated film, “Victory Through Air Power,” as well as a few of the hundreds of training films that the Disney studio made for the War Department or the National Film Board of Canada, such as “Four Methods of Flush Riveting” (1942).

Pinpointing the causes of a vast, global event like the Second World War is a challenging task for the historian. Events—especially enormous, multifaceted events—have multiple causes and multiple inputs.

To help analyze the effects of those different inputs, historians often classify an event’s causes into different categories. A proximate cause is an incident that appears to directly trigger an event, as the election of Abraham Lincoln in November 1860 and the shelling of Fort Sumter led to the outbreak of the Civil War. Such dramatic incidents are often the ones we think of as “causing” an event, since the connection between the trigger and the outcome appears both direct and obvious.

In their attempts to explore cause and effect, however, historians often probe more deeply beyond the “triggers” to locate trends, developments, and circumstances that contributed equally, if not more, to events. In the case of the Civil War, for example, historians often point to the growing sectional polarization that divided the nation in the 1840s and 1850s, the national debate over the future of slavery, and the divergent economic paths that distinguished North and South during the antebellum period. Those factors created the backdrop against which Lincoln’s election and the shelling of Fort Sumter led to full-blown armed conflict in the spring of 1861; those conditions contributed to a state of affairs in which a triggering event could exert such enormous influence and touch off a four-year war.

In the case of the Second World War, historians generally point to a series of conditions that helped contribute to its outbreak. The unbalanced Treaty of Versailles (which forced a crippling peace on Germany to end the First World War) and the global depression that enveloped the world during the 1930s (which led to particularly desperate conditions in many European nations as well as the United States) usually emerge as two of the most crucial. Those conditions formed the background against which Adolf Hitler could ascend to the position of German Chancellor in the 1930s.

Virtually all historians of the Second World War agree that Hitler’s rise to power was the proximate cause of the cataclysmic war that gripped the globe between 1939 and 1945. Without Hitler, a megalomaniacal leader bent on establishing a 1,000-year German empire through military conquest, it becomes extremely difficult to imagine the outbreak of such a lengthy and devastating war.

At the same time, Hitler’s rise to power did not occur in a vacuum. Much of his appeal to the German citizenry had to do with his promises to restore German honor, believed by many Germans to have been mortgaged via the Treaty of Versailles. The peace agreement forced Germany to accept full responsibility for the Great War, and levied a massive system of reparation payments to help restore areas in Belgium and France devastated during the fighting. The Treaty of Versailles also required Germany to disarm its military, restricting it to a skeleton force intended only to operate on the defensive. Many Germans viewed the lopsided terms of the treaty as unnecessarily punitive and profoundly shameful.

Hitler offered the German people an alternative explanation for their humiliating defeat in the Great War. German armies had not been defeated in the field, he held; rather, they had been betrayed by an assortment of corrupt politicians, Bolsheviks, and Jewish interests who sabotaged the war effort for their own gain. To a German people saddled with a weak and ineffective democratic government, a hyperinflated currency, and an enfeebled military, this “stab in the back” mythology proved an enormously seductive explanation that essentially absolved them of the blame for the war and their loss in it. Hitler’s account of the German defeat not only offered a clear set of villains but a distinct path back to national honor by pursuing its former military glory.

During the 1930s, Hitler’s Germany embarked on a program of rearmament, in direct violation of the terms of the Versailles Treaty. German industry produced military vehicles and weapons; German men joined “flying clubs” that served as a thin pretense for training military pilots. Rearmament and militarization provided appealing avenues for Germans seeking some means to reassert their national pride.

Hitler’s racial theories provided more context, both for his explanation of defeat in the First World War and for his plans for a 1,000-year German empire. In Hitler’s account, Communists and Jews—whom Hitler depicted as stateless parasites who exploited European nations for their own gain—had conspired to stab Germany in the back in 1918. Creating the 1,000-year Reich required the creation of a racially pure cohort of blond-haired, blue-eyed “Aryans” and the simultaneous liquidation of ethnic undesirables. Hitler’s vision of a racially pure German nation expanding across Europe, combined with his aggressive rearmament programs, proved a powerful enticement for the German people in the 1930s. Politicians in Britain, France, and the United States, encumbered with their own economic troubles during the global depression, were reluctant to act to check Hitler’s expansionism without irrefutable evidence of his ultimate intentions.

Only later would the world learn that those intentions revolved around the methodical military conquest of Europe from the center outward, a process one historian of the Second World War has likened to eating an artichoke leaf by leaf from the inside out. That conquest began with the German invasion of Poland in 1939 and the attack on France and the Low Countries six months later. Hitler’s quest for more “living-space” for his empire led to the invasion of the Soviet Union in 1941. By March of 1942, Hitler’s fanatical desire to conquer Europe—along with Japan’s concurrent push across East Asia and the Pacific—had plunged the world into a war that would last nearly six years and cost the lives of more than 50 million soldiers and civilians: by far the largest catastrophe in human history.

During the months preceding the attack on Pearl Harbor, the war in Europe had essentially boiled down to a contest between the Axis Powers of Germany and Italy, and against them, the Soviet Union and Great Britain.

Six months before Pearl Harbor, Germany had launched an invasion of the Soviet Union, its erstwhile ally. By December 5, two days before the Japanese attack on Pearl Harbor, German armies had advanced to within 5 miles of Moscow.

Hitler had decided to postpone a cross-channel invasion of Britain itself until his armies were able to defeat the Soviet Union, but Germany was still fighting Britain through aerial and missile bombing, and was engaged against Britain on the seas, as well as elsewhere in the British Empire, as in North Africa. In South Asia, Britain was also defending its colonies and commonwealth against Japan. On the face of it, especially in the long term and even with Lend-Lease aid from the United States, it is difficult to see how Britain could have continued the war without the entry of the United States into the conflict on its side. Presumably, Winston Churchill would have had to sue for peace, or endure a German invasion of the British Isles once the Nazis had consolidated their military strength in Europe.

That did not happen, of course. After Churchill heard that America had been attacked at Pearl Harbor, he rushed to a secure telephone to call Franklin Roosevelt. His Memoirs of the Second World War relate the following:

In two or three minutes Mr. Roosevelt came through. "Mr. President, what's this about Japan? "It's quite true," he replied. "They have attacked us at Pearl Harbor. We are all in the same boat now."

No American will think it wrong of me if I proclaim that to have the United States at our side was to me the greatest joy. I could not foretell the course of events. I do not pretend to have measured accurately the martial might of Japan, but now at this very moment I knew the United States was in the war, up to the neck and in to the death. So we had won after all!

Yes, after Dunkirk; after the fall of France; after the horrible episode of Oran; after the threat of invasion, when, apart from the Air and the Navy, we were an almost unarmed people; after the deadly struggle of the U-boat war—the first Battle of the Atlantic, gained by a hand's-breath; after seventeen months of lonely fighting and nineteen months of my responsibility in dire stress. We had won the war. England would live; Britain would live; the Commonwealth of Nations and the Empire would live.

How long the war would last or in what fashion it would end no man could tell, nor did I at this moment care. Once again in our long Island history we should emerge, however mauled or mutilated, safe and victorious. We should not be wiped out. We should not be wiped out. Our history would not come to an end. We might not even have to die as individuals. Hitler's fate was sealed. Mussolini's fate was sealed. As for the Japanese, they would be ground to powder.

United States forces played a direct role in defeating Germany, but also forced Hitler to keep huge military forces in Western Europe rather than sending them to reinforce his armies fighting against the Soviet Union, where they would likely have been a decisive factor against the Soviets. Instead, the German invasion of Russia failed after the effort that culminated at Stalingrad, and the German forces in Western Europe were eventually pushed back anyway, beginning with the landings at Normandy.

Your questions are hypothetical. They invite speculation. One of the delights of the alternate history genre of fiction is that its authors generally expend some considerable effort on the notion of history itself, especially the way in which history unwinds out of a skein of causes both large and small. In these novels, large and familiar causes and conditions and forces roll out across the world, but small human details, such as a missed appointment at the Reichs Ministry, an overlooked telegram, Hitler's mistress Eva Braun's choice of perfume on a fateful day, or a random batch of sunspots that interferes with a particular radio transmission, sometimes cascade into a vastly different history than the one with which we are familiar.