I’m pretty sure being turned back toward Mexico in the middle
of the river or on dry land shy of the US
*************
That is a legal issue for sure. Essentially the southern US/Texas border is the middle
of the Rio Grande in most places. It may vary somewhat in the major lakes, etc.
If they are in the water, turn them back at the midpoint, then watch to make sure they keep going and get out of the water on Mexican soil-no need to be fussy, just make sure they do that.
I was born and raised in rural S.W Texas, BTW-I know for certain that method works...
I know its something of a moot question(Federal employees in black robes know no law) but if a party never enters the US how can US law apply to them?