I vote yes.
1. It is a national emergency.
2. President Trump can use the military for a significant part of the building effort.
3. President Trump can even “negotiate” with Mexico for them to fund the Wall: Close the border until the Wall is built unless Mexico sends the money needed to build the Wall. We can afford that economic hit far better than they can.
4. The courts have already given mixed rulings on the question of Trump’s presidential powers. Framed as national security, this could go to the Supreme Court quickly, preventing legalistic delays.
Yes, another wave of Invaders are coming! It's Time!
Why do that? Send Mexico the specs for the desired wall and have them build it on their side.