Donald J. Trump, the 45th president of the United States, has not been in office for very long, but already the contours and characteristics of his rule have become clear. Rather than govern conventionally, through officers of state appointed for their competence and experience and with the agreement, however reluctant, of Congress, he has chosen to gather round him an informal coterie of friends, advisors, and relatives — many of them, like himself, without any experience of government at all — while railing against the restrictions imposed on him by constitutional arrangements such as the independence of the press and the judiciary.

Trump’s entourage resembles nothing more closely than the court of a hereditary monarch, with informal structures of rule elbowing aside more formal ones. Trump did, after all, win widespread support in the electorate by promising precisely this: shaking up, bypassing or overthrowing the Washington establishment and trying something new.

The result, however, has been chaos and confusion, contradiction and paralysis. It has become clear that the president of the United States is someone who does not read his briefs; who does not take the advice of experts in the intelligence field or indeed in any other; who fires off brief statements without thinking whether they are consistent with his administration’s declared policies; who is seemingly incapable of putting together a coherent sentence with a subject, a verb, and an object; who is apt to give away state secrets to a foreign power; and who seems to have no respect either for the truth or for the Constitution (not least in respect of freedom of religion and freedom of speech). He may not be mad, but a growing number of commentators allege that Trump is suffering from dementia, or is mentally subnormal, or is suffering from a personality disorder of some kind.

In a situation where a head of state is incapable of carrying out his duties properly, what guidance can history offer us? The relevant history isn’t so much the history of the presidency of the United States, where no incumbent has ever been successfully removed from office by Congress, but rather the history of incompetent — or allegedly incompetent — rulers at other times and in other parts of the world.

What happens when a political elite concludes that the real or titular head of state has to be deposed in the interests of the country as a whole? Of course, given Trump’s leadership style, the pertinent question might be narrowed down further: What happens when a monarch is judged as mentally unfit to rule?

An 1840 portrait of Ferdinand I of Austria by Francesco Hayez.

In modern times, just as further back in history, madness is a slippery concept, hard to pin down unless there are obvious signs of delusion, derangement, paranoia, or actual physical aggression.

But madness of that sort was far from uncommon in Europe’s royal families, not least because of the inbreeding favored by their convention that members of a royal family could not marry beneath their station. As Erik Midelfort explains in his entertaining 1996 monograph Mad Princes of Renaissance Germany, in 16th-century Germany nearly 30 dukes, landgraves, and counts were regarded by their courts and ministers as mad enough to require medical attention or removal from office. But what exactly was meant by “mad”? Midelfort explains that advisors and family members spoke of “weakness, folly, debility, and the condition of not being right,” or sometimes “furor, or melancholy, or sickness” when they encountered princes who seemed to be mentally unsuited to rule. The notion of clinical insanity or certifiable madness is one that only became current in the 19th century.

In the early modern period, a few princes were clearly completely deranged, like Don Julius Caesar d’Austria, son of Holy Roman Emperor Rudolf II, who tortured his mistress to death and walked about for days covered in her blood and brains, attacked his servants, destroyed his furniture, tore up his clothing, babbled and roared nonsensically, and was (allegedly) eventually strangled on his father’s orders in 1609. Some suffered from delusions, like Duke Albrecht Friedrich of Prussia, who slept in his clothes in case the Turks came for him in the night, poured his medicines on the floor, spoke to people who were not present in the room, and threw a clock at an envoy sent by Emperor Maximilian II. Relatives were appointed to carry out the business of ruling, bypassing the unfortunate duke, who was left to amuse himself with his collection of 100,000 coins while being subjected to a variety of grotesque “cures” applied by rival schools of medicine.

More common, however, was “melancholy,” or, as we would put it today, depression, sometimes attributed in the medieval or early period to demonic influences. And debilitation from such melancholy — or through paralysis or speech impediments caused by strokes, senility, dementia, and other afflictions of old age — were typically dealt with by finding someone else to rule without actually deposing the prince.

But not always. Consider the example of the 1848 revolutions in Central Europe. The fact that the Austrian Empire’s ruler, Ferdinand I, was barely capable of carrying out his duties had been known from the moment he came to the throne, following the normal line of hereditary succession in the House of Habsburg. Stories of his limited intellectual capacity were legion. When he was told one day that he could not have apricot dumplings because they were out of season, he lost his temper. “I’m the emperor,” he shouted at his cook, “and I want dumplings!” The offspring of double first cousins — his parents, in other words, shared all four grandparents — he was slow to learn to read and write, subject to epileptic fits, had a speech impediment, and was clearly incapable of carrying out his imperial duties. When he came to the throne in 1835, the country’s leading statesman, Prince Klemens von Metternich, ensured that the business of the emperor was carried out by a council consisting of himself, another politician, and the emperor’s uncle, Archduke Louis.

But this situation could not stave off the revolution that came in 1848. As the crowds marched toward the imperial palace in Vienna, Ferdinand summoned Metternich and asked “what are all those people doing there, then?” “They are making a revolution,” Metternich replied. “What, are they allowed to do that?” Ferdinand asked in astonishment. Not surprisingly, as the revolution took a grip, he was persuaded by his family to abdicate in favor of his 18-year-old nephew, who became Franz Joseph I. (The Habsburgs were always optimists, but there never was a Ferdinand II or a Franz Joseph II.) As Franz Joseph was defeated by Otto von Bismarck’s Prussian armies in the war of 1866, Ferdinand had the last laugh. “I don’t know why they appointed Franz Joseph,” he is said to have remarked: “I could have been just as good at losing battles.”

An 1816 portrait of King George IV by Thomas Lawrence,

The Habsburg Empire in the mid-19th century was in a desperate situation requiring desperate remedies, which is why the hapless Ferdinand accepted his deposition, if with great reluctance. In the case of monarchical incapacity, deposition was seldom resorted to because a general belief in the divine right of kings got in the way. If God had put the monarch on the throne — and the belief was a central part of monarchical legitimacy — then only God could remove him; mere humans had no right to. So, in more normal times, when the political structure as a whole was not under threat, abdication was typically avoided.

It was usual instead to appoint a regent to take care of royal business when the monarch became incapacitated, as for example during the few weeks in 1878 when the German Kaiser Wilhelm I was recovering from a nearly successful assassination attempt. Regents assumed all the powers of the monarch, just not the title of king.

The most famous appointment of a regent was to King George III, after he began talking to trees and speaking continuously to nobody in particular for hours on end in the early 19th century. In a rare moment of lucidity, he agreed he was no longer capable of ruling, and in 1811 conceded the appointment by act of Parliament of his eldest son George as prince regent. The prince regent, who later became King George IV on his father’s death, was not exactly a model monarch either: Addicted to opium, a heavy drinker, and a gluttonous eater, he weighed 245 pounds and had a 50-inch waistline. His extravagance and drunkenness made him unpopular, and his brother William IV, who succeeded him in 1830 at the age of 64, the oldest person to come to the throne so far, was accustomed to wander the streets off on his own, going up to ordinary citizens to speak to them (“I’m the king, you know”). The courtier and diarist Charles Greville declared that William IV “made a number of speeches, so ridiculous and nonsensical, beyond all belief but to those who heard them, rambling from one subject to another, repeating the same thing over and over again, and altogether such a mass of confusion, trash, and imbecility as made one laugh and blush at the same time.” Greville thought the king was mad, and indeed the monarch was known as “Silly Billy” by the populace at large.

But the British monarchy of the early 19th century, for all the weaknesses of its incumbents, survived because by this stage of history the kings and queens of England had very little real power. Over time, leading politicians became less hesitant to transgress alleged monarchial power that was no longer extant. It was not long before the idea of a regency fell entirely out of favor in Britain and elsewhere in Europe. When a British monarch transgressed the largely unwritten rules of the job, as King Edward VIII did in 1936 by declaring his intention of marrying an American divorcée, Wallis Simpson, the politicians had little difficulty in simply removing him from the throne. Europe’s last enactment of a regency was in the case of King Otto of Bavaria, younger brother of the eccentric Ludwig II, builder of the fairy castles of Neuschwanstein and Hohenschwangau. On Ludwig’s unexplained and sudden death, Otto succeeded to the throne, but succumbed rapidly to a deep and incurable depression, probably caused by syphilis (he was paralyzed during the final period of his life). A prince regent, Otto’s uncle Luitpold, took over for Otto, ruling from 1886 to 1912, followed by a cousin, Ludwig, who quickly got the Bavarian parliament to depose Otto and declare himself king.

In a situation such as this, the royal family’s role was at least as important as that of the political elite. Both had a strong interest in ensuring the business of government was carried on in the usual way, just not by the existing monarch. The most favored way of removing from office a monarch who has shown himself to be unfit to rule has indeed in modern times been abdication at the behest of leading politicians, usually with the support of the royal family. After the Ottoman Sultan Abdulaziz was deposed by his ministers because of incompetence, his chosen successor, his nephew Murad V, threw himself into a pool in the palace gardens, shouting to the guards to save him from assassination, and was reported to have vomited continuously for a day and a night in sheer terror. He had reason to be frightened: Within a few days it was implausibly reported that Abdulaziz had committed suicide by cutting both his wrists simultaneously with a pair of scissors. Within a few months, Murad was deposed by a coalition of family members and government ministers amid allegations of paranoia and schizophrenia, and imprisoned for the rest of his life. (Two assassinations of Ottoman sultans in a single year would have aroused too many public suspicions.) The young man was probably glad to be relieved of the burdens and cares of royal office.

Emperor Bokassa, of the now Central African Republic, stands on the throne in December 1977 after crowning himself ruler. (Photo credit: PIERRE GUILLAUD/AFP/Getty Images)

What would happen if a monarch does not cooperate with political elites who consider him deranged? In that case, removal by force becomes an option, though sometimes it can only be effected through the intervention of a foreign power. This is what occurred to the self-styled Emperor Bokassa of what is now the Central African Republic in 1979. Bokassa had himself come to power in a military coup, and almost immediately dissolved the national assembly and banned all political parties except his own. Until that point, his career was similar to that of any other tin-pot dictator.

But he soon began to show signs of megalomania. In 1976, he had himself crowned emperor, in a lavish ceremony that cost a third of his impoverished country’s annual budget. His extravagant pseudo-Napoleonic display and absurd, self-awarded titles earned him the mockery of the rest of the world, but there was a darker side to his rule: He arrested, tortured and personally murdered many of his opponents. He killed a number of schoolchildren who had thrown rocks at his car in protest against their families being forced to buy expensive school uniforms with a picture of his head on them from a firm owned by one of his many wives.

What may have done him in were the lurid allegations that he had eaten the bodies of some of his victims — or, more specifically, that he had them cooked and served up to the visiting president of France, Valéry Giscard d’Estaing. Afterward, in 1986, he was deposed and arrested by a military expedition sent by France to restore order in its former colony, and then put on trial in the Central African Republic. Found guilty on charges of murder and many other offenses (though not including cannibalism), he was sentenced to life imprisonment but subsequently released on amnesty in 1993. Meanwhile, his mental state deteriorated still further until within a few years he was claiming to be the 13th apostle of Christ.

Emperor Bokassa’s power was not only real, it was absolute, and in general it is a fairly obvious point that the more actual political power a monarch possesses, the more difficult he is to remove through legal means, and the more likely it is, therefore, that he will be coerced into abdicating, whether by his own subjects, or by outsiders.

If we look back beyond the 19th and 20th centuries to more remote periods of history, we encounter many such examples. One of very few monarchs to have earned madness as a title, the 16th-century Spanish Queen Juana la Loca, was dealt with by being forcibly confined to a nunnery. An earlier insane monarch, Charles the Mad of France, was not actually deposed, but after he murdered several of his entourage without warning in 1392 he was pushed aside by his wife and his closest male relatives and completely excluded from power. This was just as well, since his madness grew more pronounced and manifested itself in disagreeable episodes such as his refusal to wash or change his clothes for several months in 1405.

President Donald Trump speaks in the Rose Garden on June 9. (Photo credit: CHERISS MAY/NurPhoto via Getty Images)

History is littered with scores, even hundreds of examples of coups d’état, revolutions, rebellions and revolts, assassinations, murders, and other ways of overthrowing a monarch, including imprisonment and banishment. But more often than not, such incidents are political in nature: the outcome of intense rivalries of one kind or another, from family feuds to ideological upheavals.

Constitutional systems have the great advantage of channeling such rivalries into legal provisions that are almost always already in place providing for the dismissal, impeachment, or prosecution of politicians. American legal scholars have argued, for instance, that the 25th Amendment of the United States Constitution, which allows for the removal of a president “unable to discharge the powers and duties of his office,” would apply in the instance of mental debilitation.

But a note of caution is required. Donald Trump has proven unwilling to play by the rules or respect the constitution of the country that elected them. But that isn’t necessarily proof of insanity; it may just be a demonstration of his commitment to populism, which consists in showing precisely such disrespect to convention.

Populists’ contempt for the rules and conventions of politics generally gets them into trouble if ever they succeed in assuming power. A case in point is the Hamburg judge Ronald Schill, whose upstart right-wing party won 20 percent of the vote in state elections in 2001 and entered a coalition government with the moderate-conservative Christian Democrats. Schill announced he would cut crime by 50 percent, called for the legalization of cannabis, demanded that sex offenders be castrated, and urged the use of poison gas to paralyze hostage-takers (not a tactful suggestion in postwar Germany). Parents who did not bring up their children the “right way” should be jailed, he said. After denouncing German politicians in general for incompetence, he was removed from office, his electoral support collapsed, and he fled to South America, where he was secretly filmed by a German tabloid newspaper snorting cocaine.

Schill was not insane, he was merely incapable of following the rules of German politics. Like other populists, he had gained support because he promised not to play by the rules. But the rules are usually there for good reason — for example, to prevent nepotism (appointing family members as government officials and advisors), to stop corruption (using office for private gain), or to ensure a reasonable measure of consistency and responsibility in the formulation and announcement of policy. If a government is run by someone who ignores these rules, it rapidly loses in coherence and influence, both at home and abroad. It is inevitable in such situations that others in the government will ask themselves what can be done to protect it.

The only formal and legal way of removing President Trump and restoring strong and stable government is by impeachment. But as with many other aspects of the 18th-century Constitution by which the United States is still governed, this may prove a long, complicated, and difficult process. Republican members of Congress are understandably reluctant to spend many months removing a Republican president. And in the end, an attempt at impeachment may not succeed.

But that still leaves other options. If Trump rules through what is in effect the modern American equivalent of a royal court, then perhaps it is the courtiers, as in so many examples from history, together with his family, who might have to get together and remove him, or at the very least, neutralize him. The incoherence and inconsistency of his tweets and his speeches (unless they are written for him in advance and unless he sticks rigidly to the text) has prompted speculation that this has happened already.

Only a few weeks into his presidency, Steve Bannon was being described by many journalists as “President Bannon.” Now that he himself seems to have been sidelined, it looks increasingly as if Trump’s family, with Jared Kushner and Ivanka Trump alternating at the fore, is beginning to take over the show. If Americans prove incapable of deposing their debilitated president, they may soon earn the mild relief of one, or more, informally appointed American regents.