Originalism, the notion that judges should interpret the Constitution according to the meaning it had at the time it was ratified, is usually associated with expanding executive power. I suggest, however, that the opposite is true: originalism means limiting executive power. If we interpret the Constitution as understood at the time it was created, the question is: What was in the collective mind of the Colonists when they wrote and ratified the Constitution? To answer that question, I return to “the most famous sermon preached in pre-Revolutionary America”—Jonathan Mayhew’s 1750 A Discourse Concerning Unlimited Submission and Non-Resistance to the Higher Powers: with some reflections on the resistance made to King Charles. In this sermon, read as John Adams says, “by everybody,” Mayhew, thoroughly schooled in Republican thought and English constitutionalism, proposed that “unlimited submission” does not exist, and that the monarch’s powers are always limited. I conclude by drawing parallels between Mayhew’s descriptions of Charles I’s crimes and President Donald Trump’s actions since his second election.