I think it's reasonable to say that the modern trend of expansive executive power going unchecked is comparable to the mixing of religion in American politics.

In both instances they're the result of the Constitution being so old and sacrosanct that you can no longer amend it in a meaningful way. You simply change the norms, stack the courts, and you've knocked out the leg of the stool that was supposed to uphold these ideals. A modern president moving around money allocated by Congress flies in the face of the Constitution. Same with an immigration ban based on religion. But the game has changed to "us v them", and if you get enough of your team in the judiciary they'll sign off whatever you want.