were they associated with any war?
Yes, American Civil War, World War I, World War II and Cold War.
United States
Irreconcilable sectional conflict regarding the slavery of Africans and African Americans ultimately led to the American Civil War. 
who negotiated the purchase of the area south of gila river UNANSWERABLE what is this purchase all about? It is a region of present-day southern Arizona and southwestern New Mexico that the United States acquired from Mexico by the Treaty of Mesilla. how is it associated with the mesilla valley? While determining the boundaries of the U.S. and Mexico, there was a disputed territory involved a few thousand square miles and about 3,000 residents; more significantly, which included the Mesilla Valley. what can you tell me about the education of the first country mentioned above? American public education is operated by state and local governments and regulated by the United States Department of Education through restrictions on federal grants.
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United States [SEP] Civil War and Reconstruction era
Irreconcilable sectional conflict regarding the slavery of Africans and African Americans ultimately led to the American Civil War. With the 1860 election of Republican Abraham Lincoln, conventions in thirteen slave states declared secession and formed the Confederate States of America (the "South" or the "Confederacy"), while the federal government (the "Union") maintained that secession was illegal. In order to bring about this secession, military action was initiated by the secessionists, and the Union responded in kind. The ensuing war would become the deadliest military conflict in American history, resulting in the deaths of approximately 618,000 soldiers as well as many civilians.