The only recourse Congress has over a rogue president is impeachment. And we’ve seen before that Republicans won’t convict him even after he literally tried to get them all killed (and even then, the removal process relies on the justice department enforcing it, I presume?).

The courts won’t be a check either, because the Supreme Court has been happy to turn the constitution on its head for him, and even if they did, the executive branch is the one that has the means to enforce rulings.