We gave up our border with the La Paz agreement, and the border is jointly administered by a commission in Mexico City. Here is a PDF with the border zone map that is very informative. It has been highly disingenuous for the media and govt. to have ignored the La Paz agreement in any and all border issues:
http://www.nmsu.edu/~bec/BEC/Readings/10.USMBHC-TheBorderAtAGlance.pdf
Nothing showed on my screen when I tried to look at that PDF.
What was the La Paz agreement, who made it, and when?
If Congress ceded US territory from our border states, how is that any different than states themselves seceding from the US? If the Civil War told us that seceding isn’t OK, then why the heck should the feds be able to cede land from the states to foreign control (or joint federal/foreign control)?