> If the Supreme Court and Congress has no enforcement power, though, what recourse is there?
While maybe not practical for the president, but at least for various cabinet Secretaries or Directors: if they do not follow court-issued orders could be found in contempt and jailed until the corrective orders are implemented?
Trump's new doctrine is that all employees of the executive branch, such as federal police, must take his interpretation of the law as correct. So if a court ordered that the Secretary of State be jailed, Trump can issue a memo saying "the Executive Branch interprets this legal decision as meaning that the Secretary of State should not be jailed", then any federal police officer or agency head has to comply with the official interpretation of the president or be fired.
Jailed by whom? Trump controls the executive branch.