 In 1861, the Confederacy claimed the southern half of the vast New Mexico Territory as its own Arizona Territory and waged the ambitious New Mexico Campaign in an attempt to control the American Southwest and open up access to Union-held California.Confederate power in the New Mexico Territory was effectively broken when the campaign culminated in the Union victory at the Battle of Glorieta Pass in 1862.However, the territorial government continued to operate out of Texas, and Confederate troops marched under the Arizona flag until the end of the war.