Nogales nuclear war

The Nogales war, more commonly known as the Nogales nuclear war, was a conflict between the United States and Mexico that took place on 15 October 2134. Mexico, which had a far-right government under president Donaldo Luna, was threatening to invade the southwestern United States and take back the states of Texas, New Mexico, Arizona, California, Nevada, and Utah, roughly corresponding to the territory the country lost about 300 years prior in the Mexican-American War. Mexico began to produce nuclear weapons after Luna's election in 2132, and the country had an arsenal of several hundred ultra-powerful missiles at the start of the war.

Beginning of the conflict
On the morning of Friday, 15 October 2134, an American soldier named Antonio Gutiérrez attempted to cross the United States-Mexico border between Nogales, Arizona and Nogales, Sonora. He was a resident of Nogales, Arizona, and typically visited family in Santa Ana, Sonora, about 100km south of the border, several times a year. Due to the high tensions between the U.S. and Mexico and his status as a U.S. soldier, he was detained by the border guards. President Luna was notified of this by a top military aide, and, paranoid about a potential U.S. invasion retaliating against his rhetoric, Luna sent approximately 20,000 troops over the border, concentrated in Nogales, the location of Gutiérrez's arrest.

Nuclear war
U.S. President Miles Krige was notified of the Mexican army invading almost immediately, and gave the green light to nuke Mexico City as an act of retaliation. This led to a chain reaction which resulted in about 45% of the U.S. population and about 60% of the Mexican population perishing in the blasts or from radiation poisoning. Major cities nuked in the U.S. included New York City, Los Angeles, San Francisco, Kansas City, Philadelphia, Washington, Miami, Jacksonville, New Orleans, Houston, Dallas/Fort Worth, St. Louis, Chicago, Milwaukee, Detroit, Columbus, Cleveland, Pittsburgh, Minneapolis/St. Paul, Portland and Seattle.

Aftermath
Both governments were immediately destroyed in the aftermath of the war; the U.S. government was formally dissolved on 18 October 2134 after the deaths of most top officials from the aftermath of the war, and the Mexican government was formally dissolved on 16 October for the same reason. Both countries split into many separate nations in the aftermath of the war; today, 21 sovereign nations occupy the former U.S., and 16 occupy what was formerly Mexico.