Apparently they can't.
"This decision, according to a United Nations official, has violated domestic and international law. (snip) It's unknown if the United Nations will step in and take action on the issue,"
Protecting one's border goes against the UN doctrine, the "one world" doctrine.
Of course the UN wants “One World” so “they” can be king.
I’m sure that’s what obozo has been promised, but first he has to destroy the most likely opponent to the One World utopia.