As the German empire rose in power and influence at the end of the nineteenth century, skilled diplomats maneuvered this disruption of traditional powers and influences into several decades of European peace. In Germany, however, a new ambitious monarch would overshadow years of tactful diplomacy. Wilhelm II rose to the German throne in 1888. He admired the British Empire of his grandmother, Queen Victoria, and envied the Royal Navy of Great Britain so much so that he attempted to build a rival German navy and plant colonies around the globe. The British viewed the prospect of a German navy as a strategic threat, but, jealous of what he perceived to as a lack of prestige in the world, Wilhelm II pressed Germany’s case for access to colonies and symbols of status suitable for a world power. Wilhelm’s maneuvers and Germany’s rise spawned a new system of alliances as rival nations warily watched Germany’s expansion.

In 1892, German posturing worried the leaders of Russia and France and prompted a defensive alliance to counter the existing triple threat between Germany, Austria-Hungary, and Italy. Britain’s Queen Victoria remained unassociated with the alliances until a series of diplomatic crises and an emerging German naval threat led to British agreements with Czar Nicholas II and French President Emile Loubet in the early twentieth century. (The alliance between Great Britain, France, and Russia became known as the Triple Entente.)

The other great threat to European peace was the Ottoman Empire, in Turkey. While the leaders of the Austrian-Hungarian Empire showed little interest in colonies elsewhere, Turkish lands on its southern border appealed to their strategic goals. However, Austrian-Hungarian expansion in Europe worried Czar Nicholas II who saw Russia as both the historic guarantor of the Slavic nations in the Balkans and as the competitor for territories governed by the Ottoman Empire.

By 1914, the Austrian-Hungarian Empire had control of Bosnia and Herzegovina and viewed Slavic Serbia, a nation protected by Russia, as its next challenge. On June 28, 1914, after Serbian Gavrilo Princip assassinated the Austrian-Hungarian heirs to the throne, Archduke Franz Ferdinand and his wife, Grand Duchess Sophie, vengeful nationalist leaders believed the time had arrived to eliminate the rebellious ethnic Serbian threat.

On the other side of the Atlantic, the United States played an insignificant role in global diplomacy—it rarely forayed into internal European politics. The federal government did not participate in international diplomatic alliances but nevertheless championed and assisted with the expansion of the transatlantic economy. American businesses and consumers benefited from the trade generated as the result of the extended period of European peace.

Stated American attitudes toward international affairs followed the advice given by President George Washington in his 1796 Farewell Address, one-hundred and twenty years before America’s entry in World War I. He had recommended that his fellow countrymen avoid “foreign alliances, attachments, and intrigues” and “those overgrown military establishments which, under any form of government, are inauspicious to liberty, and which are to be regarded as particularly hostile to republican liberty.”

A national foreign policy of neutrality reflected America’s inward-looking focus on the construction and management of its new powerful industrial economy (built in large part with foreign capital). The federal government possessed limited diplomatic tools with which to engage an international struggles for world power. America’s small and increasingly antiquated military precluded forceful coercion and left American diplomats to persuade by reason, appeals to justice, or economic coercion. But in the 1880s, as Americans embarked upon empire, Congress authorized the construction of a modern Navy. The Army nevertheless remained small and underfunded compared to the armies of many industrializing nations.

After the turn of the century, the Army and Navy faced a great deal of organizational uncertainty. New technologies—airplanes, motor vehicles, submarines, modern artillery—stressed the capability of Army and Navy personnel to effectively procure and use them. The nation’s Army could police Native Americans in the West and garrison recent overseas acquisitions, but it could not sustain a full-blown conflict of any size. The Davis Act of 1908 and the National Defense Act of 1916 represented the rise of the modern versions of the National Guard and military reserves. A system of state-administered units available for local emergencies that received conditional federal funding for training could be activated for use in international wars. The National Guard program encompassed individual units separated by state borders. The program supplied summer training for college students as a reserve officer corps. This largely resolved the myriad of conflicts between the demands of short term state problems such as natural disasters, the fear in the federal government of too few or substandard soldiers, and state leaders who thought their men would fill gaps in the national armed forces during international wars. Military leaders resisted similar efforts from allied nations to use American forces as fillers for depleted armies. The federal and state governments needed a long term strategic reserve full of trained soldiers and sailors. Meanwhile, for weapons and logistics, safe and reliable prototypes of new technologies capable of rapid deployment often ran into developmental and production delays.

Border troubles in Mexico served as an important field test for modern American military forces. Revolution and chaos threatened American business interests in Mexico. Mexican reformer Francisco Madero challenged Porfirio Diaz’s corrupt and unpopular conservative regime, was jailed, and fled to San Antonio, where he penned the Plan of San Luis Potosí, paving the way for the Mexican Revolution and the rise of armed revolutionaries across the country.

In April 1914, President Woodrow Wilson ordered Marines to accompany a naval escort to Veracruz on the lower eastern coast of Mexico. After a brief battle, the Marines supervised the city government and prevented shipments of German arms to Mexican leader Victor Huerta until they departed in November 1914. The raid emphasized the continued reliance on naval forces and the difficulty in modernizing the military during a period of European imperial influence in the Caribbean and elsewhere. The threat of war in Europe enabled passage of the Naval Act of 1916. President Wilson declared that the national goal was to build the Navy as “incomparably, the greatest…in the world.” And yet Mexico still beckoned. The Wilson administration had withdrawn its support of Diaz, but watched warily as the Revolution devolved into assassinations and deceit. In 1916, Pancho Villa, a popular revolutionary in Northern Mexico, spurned by American support for rival contenders, raided Columbus, New Mexico killed seventeen Americans and burned down the town center before sustaining severe casualties from American soldiers and retreating. In response, President Wilson commissioned Army General John “Black Jack” Pershing to capture Villa and disperse his rebels. Motorized vehicles, reconnaissance aircraft, and the wireless telegraph aided in the pursuit of Villa. Motorized vehicles in particular allowed General Pershing supplies without relying on railroads controlled by the Mexican government. The aircraft assigned to the campaign crashed or were grounded due to mechanical malfunctions, but they provided invaluable lessons in their worth and use in war. Wilson used the powers of the new National Defense Act to mobilize over 100,000 National Guard units across the country as a show of force in northern Mexico.

The conflict between the United States and Mexico might have escalated into full-scale war if the international crisis in Europe had not overwhelmed the public’s attention. After the outbreak of war in Europe in 1914, President Wilson declared American neutrality. He insisted from the start that the United States be neutral “in fact as well as in name;” a policy the majority of American people enthusiastically endorsed. What exactly “neutrality” meant in a world of close economic connections, however, prompted immediate questions the United States was not yet adequately prepared to answer. Ties to the British and French proved strong, and those nations obtained far more loans and supplies than the Germans. In October 1914, President Wilson approved commercial credit loans to the combatants which made it increasingly difficult for the nation to claim impartiality as war spread through Europe. Trade and trade-related financial relations with combatant nations conflicted with previous agreements with the Allies that ultimately drew the nation further into the conflict. In spite of mutually declared blockades between Germany, Great Britain, and France, munitions and other war suppliers in the United States witnessed a brisk and booming increase in business. The British naval blockades that often stopped or seized ships proved annoying and costly, but the unrestricted and surprise torpedo attacks from German submarines were far more deadly. In May 1915, the sinking of the RMS Lusitania at the cost of over a hundred American lives and other German attacks on American and British shipping raised the ire of the public and stoked the desire for war.

If American diplomatic tradition avoided alliances and the Army seemed inadequate for sustained overseas fighting, the United States outdistanced the nations of Europe in one important measure of world power: by 1914, the nation held the top position in the global industrial economy. The United States producing slightly more than one-third of the world’s manufactured goods, roughly equal to the outputs of France, Great Britain, and Germany combined.