One of the great passages from Roman history comes right at the beginning of Book One of Tacitus’ Annals, where he is discussing how Augustus seized power and ended the Republic for good.

When after the destruction of Brutus and Cassius there was no longer any army of the Commonwealth, when Pompeius was crushed in Sicily, and when, with Lepidus pushed aside and Antonius slain, even the Julian faction had only Caesar left to lead it, then, dropping the title of triumvir, and giving out that he was a Consul, and was satisfied with a tribune’s authority for the protection of the people, Augustus won over the soldiers with gifts, the populace with cheap corn, and all men with the sweets of repose, and so grew greater by degrees, while he concentrated in himself the functions of the Senate, the magistrates, and the laws. He was wholly unopposed, for the boldest spirits had fallen in battle, or in the proscription, while the remaining nobles, the readier they were to be slaves, were raised the higher by wealth and promotion, so that, aggrandised by revolution, they preferred the safety of the present to the dangerous past. Nor did the provinces dislike that condition of affairs, for they distrusted the government of the Senate and the people, because of the rivalries between the leading men and the rapacity of the officials, while the protection of the laws was unavailing, as they were continually deranged by violence, intrigue, and finally by corruption.

In truth, Augustus was at pains to maintain the appearance of republican government, but gradually and by degrees he usurped every power whether legal, legislative or religious. This was made possible by his great fortune and his patience and cunning. But a key component was the moral weakness of his natural opponents who were either intimidated or bought off.

The Founding Fathers were well-versed in Tacitus’s histories and none more so than the author of the Declaration of Independence, Thomas Jefferson. He once wrote, “Tacitus I consider as the first writer in the world without a single exception. his book is a compound of history & morality of which we have no other example.” Jefferson studied the ancient historians with a particular interest in what they could teach him about fending off tyranny.

And these lessons, which also interested the other founders of our country, helped shape first the Articles of Confederation and then the Constitution and the Bill of Rights. Chief of among the lessons was the importance of separation of powers between the executive, legislative and judicial branches, and along with this, the religious, speech and assembly protections of the First Amendment.

But these protections are inadequate if the legislative and judicial branches give their power away to the executive branch. This is true when it comes to how money is distributed and spent, and it’s true when it comes to control of the military and whether the military can operate on domestic soil.

We can see from the following passage in the Declaration of Independence how Jefferson took the example of Augustus’s creeping despotism as a warning.

Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.

Tacitus had described this “willingness to suffer” as a readiness of nobles to become slaves. Jefferson made the link to the colonists’ experience under the capricious rule of King George III. But Jefferson knew he wasn’t living under a Republic. It was when he chose to recreate one based on the Roman example, that he sought to create safeguards that the Roman Republic needed but lacked.

Where he must, Trump will raise his rivals “higher by wealth and promotion, so that, aggrandised by revolution” they prefer “the safety of the present” to the dangers of opposition. Generals who go along with his plans to use the military to crush domestic opponents will fit this description. Senators who genuflect before him rather than insist on their own powers of the purse fit this description. And Supreme Court Justices who will not enforce the Constitution fit this description. We have seen it all before.

And we are here again. We have new duties. But these duties are not new.