Impeachment is perhaps the most tenuous and insubstantial concept in the legal tradition of the Anglosphere. There are no experts on impeachment, for the uncomplicated reason that impeachment has not succeeded in the terms envisioned by law professors in more than 400 years. As in the United States, where it has failed three times to remove a president from office, so too in Britain has the impeachment of ministers been a largely inconclusive affair. To speak (as the witnesses called to testify on the subject before the House Judiciary Committee did last week) of impeachment as if it were a routine matter, with well-defined parameters and satisfactory legal outcomes, is simply farcical.

Here the centuries-long record of impeachment in Britain, to which the president's opponents have attempted to draw attention recently, is instructive. Its history is one of uncertainty, factionalism, and mob rule.

Impeachment emerged out of the jungles of English common law in the Middle Ages, when it was restricted to peers. By the end of the 15th century it had fallen into disuse, only to be revived under the Stuarts by a series of jealous Parliaments. Twice the House attempted to impeach the Duke of Buckingham, the great favorite of James I, and twice the monarch dissolved the assembly. Here matters would not be allowed to rest, even after James' death. It was asserted by many that the duke's wrongdoing could be laid at the feet of the John Lambe, his private physician. This avowed sorcerer, who for a fee of £50 insisted that he could discover the location of stolen objects in his crystal, was stoned to death by a mob. But still Buckingham's enemies cried:

Let Charles and George do what they can,
The Duke shall die like Doctor Lambe.

On August 23, 1628, he was murdered in a Portsmouth tavern.

In the following decade, the Earl of Strafford would make many enemies while serving as lord deputy of Ireland. Upon his being recalled to England, he found himself the subject of impeachment proceedings. These were dropped when, after an exhaustive examination of his conduct, no impeachable offenses could be found. Instead a bill of attainder — the preferred method of procuring judicial assassinations in the previous century under the Tudors — was passed in the Commons. Strafford was imprisoned, but King Charles swore that no harm would befall him, and the Lords seemed reluctant to take up the attainder. Alas, a ludicrous plot by His Majesty's servants to storm the Tower of London and thus extra-judicially restore Strafford to liberty was exposed. The bill passed. The king consulted his bishops, who assured him that he could in good conscience renege on his promise to Strafford, who himself begged Charles to permit his execution for the sake of the kingdom. Among Charles' last words in 1649 were his avowal that his own beheading was divine retribution for "that unjust sentence which I suffered to take effect." One of the first acts taken by Parliament upon the restoration of the monarchy in 1660 was the official expungement of the attainder on the grounds that it had been "treasonable and scandalous."

The unfortunate earl is, so far as I am aware, the last person to have been killed as a direct result of an impeachment inquiry. After his death the process would destroy only fortunes and reputations.

Warren Hastings, the first governor-general of British India, knew Bengali, Urdu, and Persian, among other languages. He wrote the introduction to the first English translation of the Bhagavad Gita and devoted a considerable amount of his time and resources to the study of Sanskrit. After serving for 10 years as governor-general, Hastings returned to England in 1785, where he showered his friends with presents, among them "a certain richly carved ivory bed which the Queen had done him the honour to accept from him." Even before his arrival it had become clear that he would find himself on the receiving end of a great deal of abuse from the Whig minority in Parliament, who accused of him of various misdeeds, including the use of excessive force in a variety of conflicts with minor native rulers.

The question of Hastings's responsibility is one that has never been adequately settled. It is certainly odd to think of a man who once claimed that he "loved India a little more than I do my own country" of being a genocidal maniac. Lytton Strachey, no friend of imperialism, once called Hastings "the best-abused personage in history." Nearly all historians now agree that Hastings was, by the standards of his contemporaries in India, a man of humane and enlightened views, and that his alleged misdeeds were of mostly instrumental importance to the opposition party at home, which sought to embarrass the Tory administration. It took Edmund Burke days to read the articles brought against Hastings in 1787, and the process would drag on until 1795, when he was finally acquitted in the Lords. By then his legal defense had cost him more than £70,000.

A few years later, impeachment was again taken up by the Whigs. Despite the ample evidence of his financial mismanagement — which was ubiquitous in British politics at the time among members of both parties — and his impeachment by the Commons in 1806, the Tory Viscount Melville was also acquitted in the Lords. This was the least ambiguous case in two centuries, but it did not succeed, in part because there was no clear statutory offense that corresponded to his behavior, in part because Melville's own party controlled the balance of power in the upper chamber.

A far less deserving target of similar proceedings was Caroline of Brunswick, the unfortunate wife of King George IV. The two had been married in 1795 at a ceremony during which George, who was then the prince regent, was drunk. He hated his wife and sought to prevent her from becoming queen by any means necessary. Rumors were circulated that she had engaged in adultery and even given birth to an illegitimate child; these were investigated and found baseless. (A similar inquiry would not have reached the same conclusion about the conduct of the regent himself, who, among other things, had secretly married the Catholic Maria Fitzherbert in 1795.) When impeachment faltered, legislation was introduced in 1820 to "deprive" Caroline of her title and dissolve her marriage on the grounds that she had "carried on a licentious, disgraceful, and adulterous intercourse" with an Italian commoner named Bartolomeo. The ensuing debate on the floor of the Commons was effectively a trial in which she had no rights. The British people were appalled, and when the so-called Pains and Privations Bill failed in the Lords the windows of newspapers that had supported it were smashed to pieces. When George was finally crowned king the following year, she was not permitted to attend the ceremony. A weeks later she died. His Majesty did not attend the funeral.

Decades later, Lord Palmerston would be the object of the last serious attempt at impeachment in English history. In 1848, his rivals charged that he had entered his country into a secret treaty with the Russian imperial government. The vote failed. In 2004, a Welsh MP announced his intention of impeaching Tony Blair, only to be told by Peter Hain, then the leader of the Commons, that impeachment had "died," perhaps as long ago as 1867, when suffrage was expanded by the Second Great Reform Bill. (Among the handful of supporters of this failed motion was one Boris Johnson.)

Male witches, Irish officials, Urdu scholars, ornate furniture, shadowy diplomatic back channels, manipulation and vilification of the press, men behaving swinishly towards women: This exhausts the modern history of this supposedly well-established trans-Atlantic constitutional process.

What does it tell us about President Trump's increasingly likely impeachment and acquittal? Perhaps it depends upon the view one takes of the relationship between the British and the American understandings of impeachment. If one adopts the (to my mind sensible) position that there is no meaningful connection between an ancient procedure for trying ministers of the crown without obtaining the sovereign's permission and an eponymous but otherwise unrelated provision of the U.S. Constitution of 1788 as it is understood 231 years later, then it is difficult to glean anything of importance from the history of British impeachment proceedings. This is not only because the president's position lies somewhere between that of a British minister and the crown itself — not only the head of the federal government but also the head of state from whom federal legal authority proceeds — but because Britain in the 17th, 18th, and 19th centuries (to say nothing of the 14th) is not the United States in the 21st.

If on the other hand one believes, as the expert witnesses called by the Democrats appear to do, that there are certain immutable principles in the common law that transcend time and space, uniting the cases of Buckingham, Strafford, Hastings, Melville, and Palmerston with those of Andrew Johnson, Richard Nixon, and Trump, then the precedent in both the United States and Britain is clear: Trump ought to be impeached in the House, which numbers the harassment of political foes among its prerogatives, and acquitted in the Senate, which is controlled by Trump's allies. Impeachment, on this understanding, is simply an emotional failsafe mechanism, a release-valve for partisan rage that would otherwise be pent up.

Once more we hear the great machine start. Gears turn, bolts tighten while lubricant is applied; we hear a hiss and smoke rises above the din — then it stops. When one stoops to inspect the heap of scrap metal one finds that it was last inspected in 1998. Perhaps it will run better next time.