There really isn't anything the Trump administration can or should do about this, aside from registering the usual protests.
Mr. Warmbier took it upon himself to travel to a dangerous and unstable place where nearly all (if not all?) Americans are viewed with contempt and suspicion.
The treatment he received there was (of course!) unwarranted.
But travel there comes with great risks.
He chose to take the risks, and he paid a price for so doing.
RIP.