1920: America's Great War is an alternate history novel by Michigan economics professor Robert Conroy. It was first published as an ebook by Baen Books in November 2013; a hardcover edition followed in December of the same year, and a paperback edition in March 2015.
The novel depicts a fictional world where Imperial Germany had emerged victorious early in World War I, and launches a surprise invasion of the United States in the year 1920 from Mexico. The book's premise is based on an actual plan Germany had proposed to Mexico during the Great War.
The novel's prologue sets the point of divergence in early September 1914 where, at the First Battle of the Marne, the German Army overwhelms the French and pushes on to capture Paris. France surrenders and the Allies sign the Treaty of Princeton, thus ending the War of 1914 (World War I in our timeline) with the Central Powers victorious.
The novel then jumps to the summer of 1920 in the United States, where U.S. President Woodrow Wilson, praised for acting as mediator to end the European war, runs for a third term despite being bedridden. Thinking a lasting peace had been achieved, he had then enacted strong isolationist policies and cut the budget for the U.S. military. The impression proves illusory. German Emperor Kaiser Wilhelm II views the United States as the only remaining nation that can threaten Germany, and prepares for war. He aids the revolutionary forces of Venustiano Carranza in overthrowing the government of Mexico, which then becomes a German ally. The plan is to launch a joint German-Mexican surprise invasion into the Southwestern United States to gain the U.S.'s vast natural resources for Germany and recover territory lost to the United States in the previous century for Mexico.
When Woodrow Wilson has died in his sleep and Vice President Thomas R. Marshall steps down, feeling himself unequal to the responsibility of the U.S. presidency, Secretary of State Robert Lansing is sworn in as president instead. Aware of the invasion threat, President Lansing has the U.S. military desperately scramble a defense, which comes too little and too late as the German Army crosses the border into California and the Mexican Army crosses the Rio Grande into Texas.
Due to the military budget cuts, the U.S. Army is poorly trained and equipped, thus is easily overrun. German saboteurs cut vital railroad links and telegraph lines, severing most communication between the southwestern states and the rest of the country. San Diego and Los Angeles fall into German hands, while the Mexicans burn Laredo and Brownsville. The Imperial German Navy's Pacific Fleet blockades West Coast ports, bombards coastal towns and traps the U.S. Navy's fleet in San Francisco Bay and Puget Sound. Forced to retreat north, the Americans destroy the refineries of the Los Angeles City Oil Field to deny fuel to the enemy's mechanized Army units and the blockade fleet, slowing the invasion. Meanwhile, the Texas Rangers and the National Guard fight a brutal defensive trench war that significantly impedes the Mexicans.
As the U.S Army in California fortifies San Francisco and the American public rallies to raise more troops to repel the invaders, the United Kingdom quietly smuggle weapons, equipment, and military advisers to the U.S. through Canada. From the fall of 1920 to the winter of 1921 the Germans slowly advance to San Francisco as a belated flu epidemic that kills nearly a million people across the country. The Americans strike back by sinking German resupply freighters with submarines, and repulse the Mexican advance after a bloody ″Second Battle of the Alamo.″ A re-equipped U.S. Army under John J. Pershing drives the Mexicans back across the border. Carranza is assassinated by Pancho Villa and Mexico falls into chaos until Alvaro Obregon takes over and asks President Lansing for a status quo antebellum. Lansing agrees to on condition that the U.S. Army receive right of passage through Mexican territory westwards so it can retake California from the Germans.
On the eve of battle for San Francisco, General Nolan is killed by German stormtroopers and Ike Eisenhower is promoted to lead the defense of the city. The German Army finally reaches San Francisco and begins a brutal siege led by Kaiser Wilhelm II's son, Crown Prince Wilhelm. The German Navy blockade ships enter San Francisco Bay to assist, but are surprised by an aerial bombardment of U.S. Army Air Corps biplanes led by Colonel Billy Mitchell and flown by civilian volunteers like Amelia Earhart. As the remaining ships flee the Bay, they are engaged in ship to ship battle with the remaining battleships of the U.S. Navy's Pacific Fleet, the USS Arizona, the USS Pennsylvania, and the USS Nevada. The battle ends in stalemate as German battleships Koenig and Thuringen are sunk, and the Bayern runs aground, while the Nevada is sunk, the Arizona beached, and the Pennsylvania badly damaged.
U.S. Army reinforcements reach San Francisco just as the city defenses are overrun, and before the Germans' new mass stormtrooper force can take the city a surprising American counterattack using smuggled British tanks crashes through their troop formations. The German Army retreats, and Crown Prince Wilhelm is killed by a sniper. The invasion force is eventually cornered in Monterey Bay by U.S. forces from San Francisco and from Pershing's force from the south. The Germans surrender.
Meanwhile, in Russia, Leon Trotsky leads a second revolution that causes Tsar Nicholas II to flee to Germany. To caputre him, the new Soviet Union launches a massive invasion. Humiliated by the defeat in the United States, and morning the loss of his eldest son, Kaiser Wilhelm II steps down; his second son Prince Eitel Friedrich takes over and sues for peace with the United States in order fight the Soviets. President Lansing agrees but forces Germany to pay reparations. The novel ends as peace is negotiated and Lansing and discusses with Winston Churchill the possibilities for the new weapons that were used in the war.