Of course, the Founders used "enemy" as meaning a nation which was at war with us not the concocted "war" you would like to accuse the Mexican Government.
Words have their meanings and they are not subject to the pliable and false definition you wish them to.
Hence, your argument for treason falls apart with a mere examination of the term. I would easily defeat any argument based upon the completely subjective and unrealistic interpretation you are reliant upon. Trivial.
Exhibit one: A pamphlet printed by the Mexican Government informing would be invaders of the best routs into the United States.
Exhibit Two:
Mexican Consulates in the United States advising their citizens who are here illegally how best to circumvent US immigration law.
Exhibit Three:
Mexican propaganda calling Mexican citizens who break US immigration laws "Hero's"
Exhibit four:
Mexican ambulances pulling up to the US/Mexico border to drop off patients to be taken into US emergency rooms.
Exhibit five:
Mexican military troops violating sovereign US territory for the express purpose of assisting Mexican drug cartels in delivering illegal substances into the United States.
Exhibit six:
Mexican diplomats arranging for fraudulent documentation to be provided to illegal aliens for the express purpose of circumventing US labor laws.
Need I go on. Are these people not our enemies? Are the US officials providing intelligence to the Mexican government not traitors as defined by the US Constitution? If you think not then you are a fool assisting in the systematic destruction of your country.