The Border Crisis Won't Be Solved at the Border

It may be worth noting that a significant proportion - 42% - of "other-foreign-nationals" or "undocumented immigrants" arrived here at airports or other ports with a legal visa, and then overstayed their visa, thus never crossing the "border" (implicitly with Mexico) that looms large in all discussions of this topic.

[1]https://sgp.fas.org/crs/homesec/R47848.pdf#:~:text=An%20esti....

So those immigrants are actually "documented", in some way, because they have got their visa after passing some screening processes.

they "were documented" -- who knows if they're still at their stated location / job / school / whatever.