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)?
Try updating the PDF reader. The link works just fine. I like www.ixquick.com as a search engine. Try searches using US/Mexico border agreement, US/Mexico La Paz agreement.
Another link...http://www.cdc.gov/USMexicoHealth/about-border-region.html
Groups like La Raza and Azteca want the line from East Texas to WA State returned to Mexico/Hispanic culture...see the second map and draw a line. The North American Union idea does not oppose it.