War powers act gives him the legal authority.
What’s your point? If he has presidential authority to act against terrorist in foreign countries - and to build walls and forts in Syria, Afghanistan and Iraq - then he has authority to protect our own border with a wall against invaders It’s called commander in chief. Unfortunately he let Paul Ryan talk him out of it - the same Paul Ryan who has a big wall around his house
My point is he’s doing what he LEGALLY can.
Would you prefer the president break the law? If you prefer that, vote for a democrat next time.