“Legal I dont know:”
He has total authority over national security. If congress wants to impeach him over securing the borders, then they’ll impeach him over anything. Besides being under the gun of the corrupt state, another possibility for his inaction maybe outright insubordination. I’m at a loss to explain it.
But I’ve heard that troops to the border have no authority to detain, arrest or deport. Only the Border Patrol can do that.
Why not just lay down 10 rows of razor wire and have 1,000 hum vees patrol 24/7? If you cut through, you are printed and deported. No asylum .never.