Caren,
I can't imagine this having legs. Remember that Trump built only 50 miles of wall.
But the stir plays to his crowd, and combativeness maintains the grift.
There will be substantial resistance to uprooting immigrants. It's way more complicated than shutting a gate. Unfortunately, even the suggestion of mass deportation does harm. Chickens will remain unslaughtered; farmhands will go walkabout, and forget replacing the roof.
The military would be reluctant because it would divert brains and manpower from its mission of safekeeping America, and its role would be confused. However, in Donald's world, the Police and the army, wearing uniforms and carrying guns, are undoubtedly interchangeable.
Best.