World War I: The U.S. ambassador Walter Hines Page to the United Kingdom is given the Zimmermann Telegram, in which Germany pledges to ensure the return of New Mexico, Texas, and Arizona to Mexico if Mexico declares war on the United States.

World War I or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Main areas of conflict included Europe and the Middle East, as well as parts of Africa and the Asia-Pacific. There were important developments in weaponry including tanks, aircraft, artillery, machine guns, and chemical weapons. One of the deadliest conflicts in history, it resulted in an estimated 30 million military casualties, plus another 8 million civilian deaths from war-related causes and genocide. The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic.

Walter Hines Page was an American journalist, publisher, and diplomat. He was the United States ambassador to Great Britain during World War I. After World War I broke out in 1914 Page was so enthusiastically in favor of Britain during the period of American neutrality that Wilson and other top officials increasingly discounted his views. Page was instrumental in negotiating the sale of American war materials, including munitions, food and supplies, to the British, helping to ensure that it had the resources it needed to continue the fight against Germany.

The Zimmermann telegram was a secret diplomatic communication issued from the German Foreign Office on January 17, 1917, that proposed a military contract between the German Empire and Mexico if the United States entered World War I against Germany. With Germany's aid, Mexico would recover Texas, Arizona, and New Mexico. The telegram was intercepted by British intelligence.

New Mexico is a state in the Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also borders the state of Texas to the east and southeast, Oklahoma to the northeast, and shares an international border with the Mexican states of Chihuahua and Sonora to the south. New Mexico's largest city is Albuquerque, and its state capital is Santa Fe, the oldest state capital in the U.S., founded in 1610 as the government seat of Nuevo México in New Spain. It also has the highest elevation of any state capital, at 6,998 feet (2,133 m).