lmm parent
Why? Blatantly unconstitutional searches at the border have been going on for decades under administrations from both sides. The US public very evidently doesn't care about the rights of people entering the country. Trying to do the same thing to citizens away from the border will be a different story altogether.
The US Supreme Court has long held that the border mitigates "reasonable" in the 4th amendment such that warrantless searches at the border are constitutionally sound. [0]
That said, this isn't a search. It is the presumption of guilt if a search is refused. I agree with you that it's bad policy, but it's not unconstitutional.
Just because both sides might do it doesn’t make it right.