We could speculate on how presidents without fear of the law might act, but we already have a historical example in Trump’s favorite president, Andrew Jackson.
In 1831, the Supreme Court decided 5–1 in favor of a pair of missionaries who had been assisting the Cherokee in a dispute with the Georgia state government. The justices ruled that because the Cherokee constituted a sovereign nation, only the federal government had jurisdiction over them. Georgia had passed a series of laws authorizing the ethnic cleansing of the Cherokee from any lands claimed by the state, and as a result of the ruling, those laws had become invalid. But Jackson had no intention of upholding the Supreme Court’s decision and preventing Georgia from seizing those lands and displacing the Cherokee.
According to the Jackson biographer Jon Meacham, the president did not say, “Well, [Chief Justice] John Marshall has made his decision, now let him enforce it,” the popular misquote of Jackson’s reaction. Instead he said, “The decision of the Supreme Court has fell still born, and they find that it cannot coerce Georgia to yield to its mandate.” But the effect was the same. Neither Jackson nor the state of Georgia wanted to follow Marshall’s opinion, and so they ignored it. The federal government had already passed the Indian Removal Act in 1830, so the decision would not have prevented the ethnic cleansing known as the Trail of Tears even had it been heeded. Nevertheless, the incident showed that the Supreme Court had no power to enforce its decisions; it relied on the good faith of the executive branch.
In the history of presidential crimes, the ethnic cleansing of Native Americans dwarfs anything Trump has done. Jackson acted as he did not because he believed that the text of the Constitution granted him immunity, but because in 1831 the United States allowed only white men to vote and there was no constituency large enough to oppose his actions. In other words: He did it because he knew he could get away with it.
One could retort that the fact that the republic did not fall after a president ignored a Supreme Court decision should provide some comfort. But that is not the lesson here. The lesson is that presidents and governments are capable of doing monstrous things to people they consider beneath them or to whom they are unaccountable. The extraconstitutional presidential immunity invented out of whole cloth by the Roberts Court offers to make presidents unaccountable not just to a portion of the people they govern, but to all of them.