However Donald Trump leaves the White House, whether through impeachment, defeat at the polls or (God forbid) after a second term, there will be a reckoning in U.S. politics. For nearly three years now, a corrupt, authoritarian presidency has hacked away at democratic institutions and safeguards. Trump has surrounded himself with self-enriching cronies, conspiracy-minded propagandists and, yes, even criminals.

Trump himself has committed a panoply of impeachable offences. As an unnamed co-conspirator in the case against his former fixer Michael Cohen, Trump directed the commission of a crime. He likely attempted (or succeeded in) obstructing justice in the Russia probe. He has not, despite his promises, divested from his businesses and is making a profit from foreign governments, in violation of the constitution.

Pressuring Ukrainian President Voldoymyr Zelenskyy to investigate a political rival is just a high note in this opera of malfeasance. Now, he is refusing congressional subpoenas, trying to cover up his impeachable actions and taking a hatchet to the rule of law in the process.

Trump is committing these impeachable offences and possible crimes all the while tearing up U.S. foreign policy. He has abandoned the Kurds to almost certain genocide in Syria; he is fulfilling Russian President Vladimir Putin’s policy goals in Ukraine and the Middle East and he continues to attack NATO allies through his deliberate misunderstanding of the organisation’s finances.

And for almost three years, he’s faced no consequences. Certainly, this is partly due to Republican ultras in the House and, especially since 2018, the Senate. But there is a more fundamental problem. The U.S. president is simply too powerful.

The American presidency is akin to an elective kingship. The president has vast, sweeping and frequently unregulated powers not unlike the Caesars of the early Roman Empire. And like in Rome, a venal or amoral or mentally unfit man can wield those powers against the people and against the traditional institutions that ostensibly keep him in check.

We’ve seen all this before. Richard Nixon’s administration was a criminal cabal with the president at the centre. George W. Bush allowed his cabinet to wage an illegal war and a campaign of torture. Ronald Reagan’s administration effectively committed high treason in the Iran-Contra Affair. And on and on it goes, back through history to the corruption that drove Warren Harding to an early grave, and beyond.

Despite every lesson about the dangers of an overmighty presidency, neither Republicans nor Democrats have ever seriously advocated for reform. This inaction is based on three premises: that a ‘good man’ will always be president; that the constitution will check a bad president and that if they scale back the president’s powers, those powers won’t be available to the next president from their party.

That the ‘good man’ argument is false needs no explanation.

Can the constitutional ‘checks and balances’ impede a villain in office? To some extent, yes. The obvious example is Nixon, who resigned once Republicans in Congress learned the truth about his crimes. Yet by then so much of the damage was done. And but for certain fortuitous circumstance (a disgruntled whistleblower) Nixon might have gotten away with it.

So with Nixon, even more so with Trump. If he were to leave office tomorrow, the damage he’s done would still be very hard to undo in many areas, irreparable in others. In most cases, by the time the checks and balances kick in, they’re nothing more than palliative care. The president is just too powerful.

The final argument against restraining the presidency amounts to ‘Our guy will use the power properly.’ This fails on principle, but also in practice. The key point here is: Democrats abuse their power as well.

Republican Senator Rand Paul was right when he filibustered against Barack Obama’s power to kill people in foreign countries with drones. Lyndon Johnson was wrong to lie to Congress about the Gulf of Tonkin Incident; John F. Kennedy was wrong to hide his Addison’s Disease from the public, and the less said about the Clintons, the better.

The constitutional fetishists should know that America’s Founding Fathers never intended the country’s ‘chief magistrate’ to grow so powerful, nor could they have imagined it.

To prevent another President Trump, the presidency itself must be diminished. Congress must reclaim the power to make war and peace. The White House must submit to greater scrutiny and be legally required to do so. Measures should be put in place to detect presidential malpractice early on, stop it, and punish it. None of this should require changes to the constitution, just changes to the law and political culture.

But the political parties must also reform themselves. Their processes for choosing a presidential candidate should not be a free-for-all. Trump was able to waltz into the Republican primaries in 2016 with no long-standing membership of the party and no experience of public office. Similarly, independent Senator Bernie Sanders fades in and out of the Democratic Party as the electoral season dictates. These practices must be brought to an end.

If it takes this horrific circus of a presidency to teach America’s political establishment that only fundamental change will protect the country, and the world, from unfit presidents, it is a price worth paying. History, however, suggests we will be short-changed.

Robert De Niro says Trump is a “weird twisted president who thinks he’s a gangster”