This should cause Mexico great pain but what else?
It will cause great pain for a lot of Americans but what would closing border actually accomplish?
Would migrants turn around and walk back to Central America?
Would Mexico arrest people that aren't breaking any law?
Would Mexico shelter and feed these people?
Lastly would it reduce illegal immigration?
The answer is obviously no to all the above. What it would do is create a real emergency on southern border and declare to world that the most powerful nation on earth can't protect it's own borders.