The justice system can only act on cases that are brought to it. Uniformly agreed that if someone had brought a suit against DACA it would have been declared unconstitutional. But no one ever brought a suit, so no court case ever held. So the justice system could not act.

Trump is undoubtedly doing the right thing. By making the lawmakers in Congress write a law that addresses immigration. That is their role.

Congress has been falling down on their job for more than 8 years. They need a kick in the pants