In the years after the secession of New York and Texas, the fragmentation of the United States became chronic, with alliances between different seceding states taking hold. the Native American Navajo and Lakota tribes took up arms and seized a large portion of territory in the American West. With little Federal opposition, the Natives managed to secure a fairly broad section of territory. Because borders are in effect within the former United States, air transport is key to commerce, giving way to air piracy and the formation of a new type of criminal group.