Congress can at any time rescind their authorization for the president to use his discretion on any given topic.
Congress allowed Obama to throw open the borders without vetting invaders, and Congress allows Trump to re-institute strict vetting.
Congress WANTS to evade responsibility, hoping voters will just blame the president instead of them. The Executive Branch is designed to respond to the president in the absence of enforced directives from Congress.
BINGO!
The Executive Branch is designed to respond to the president in the absence of enforced directives from Congress.
WRONG!
The Left has usurped the Constitution by allowing Congress to not do its job and letting the Executive Branch become a pseudo dictatorship.