"It's not quite as bad as I had anticipated. Still, it comes awfully close to being an act of war."
It is an Act of War as it is indeed a violation of the Treaty of Guadalupe-Hidalgo (1848) that estalished the border. Specifically as detailed in Article V, paragraph 4:
"The boundary line established by this article shall be religiously respected by each of the two republics, and no change shall ever be made therein, except by the express and free consent of both nations, lawfully given by the General Government of each, in conformity with its own constitution."
We have the right to militarize the border under Article XVI:
"Each of the contracting parties reserves to itself the entire right to fortify whatever point within its territory it may judge proper so to fortify for its security."
And we should do so.
If the country of Mexico is an ally, we are in deep, you know what.
They refused to back the US in the Iraq war. The president said if you aren't with us, you're against us. What the he!! happened to that?