Massivedesign wrote:
.....Does this count as Treason?....
No, but Mexico CAN construe this as an act of war. Intentional arming a group subversive to the authoritative body of the Mexican government, leading to the injury, kidnapping, and death of many many Mexican citizens and government officials.
They can sue the US, and ask for reparations. They don't even have to name anyone specifically in the suit.