Frank Augstein / AP

These days, it is rare that a piece of political news can make your jaw drop. But the suspension of Jeremy Corbyn from Britain’s Labour Party lit up social media—and my phone—like a fireworks display.

Until April, Corbyn was the leader of Britain’s main opposition party. (He stood down less than four months after leading Labour to a thumping general-election defeat last year.) The man who replaced him, former lawyer Keir Starmer, supported the punishment.

The immediate cause of Corbyn’s suspension was his reaction to an independent report, published this week by the Equality and Human Rights Commission, a British watchdog group, on anti-Semitism within the Labour Party. The report found that his office had interfered with complaints about anti-Semitic postings and comments, objected to an investigation into Corbyn himself, and contributed to a hostile environment for Jews in the party. Significantly, it found that the offenses amounted to three breaches of equalities law. One section was entitled “A Failure of Leadership.”

In this context, taking action against the man who oversaw this failure might seem obvious. Yet our political climate encourages partisans to dismiss or even cover up wrongdoing by their side. The American comparison underlines how extraordinary Starmer’s action is. If Donald Trump loses the upcoming U.S. presidential election, absolutely no one expects the Republican leadership to repudiate his racism, sexism, and contempt for democracy. There will be no reckoning with the man who corrupted the values of his party. In a hyper-partisan era, the temptation to excuse and obfuscate the mistakes of one’s own side will surely prove irresistible, even to those who have privately expressed their disgust with the president.

The most extraordinary aspect of Corbyn’s suspension, then, is also the most basic one: A party leader has disciplined his predecessor. (Labour insists that the decision was not taken by Starmer personally—but he created the “zero tolerance” rules which made it inevitable, and it was his chosen candidate for the party’s top official who wielded the axe.) Starmer won the leadership in part because he did not denounce Corbyn, as other Labour politicians did. Indeed, he served in party leadership under Corbyn. He is far from the British equivalent of a Never Trumper. Yet it is under his command that the party has severed the link with its most recent leader. It’s not regicide or patricide, but it feels close to both.

Corbyn’s reaction to the anti-Semitism report was typical of his attitude to the broader issue, which has dragged on for several years. In a Facebook post, he said he regretted the slowness of reforming the complaints procedure under his leadership, but argued that Labour’s anti-Semitism problem had been “dramatically overstated” by his opponents and the media. He used a favorite phrase—denouncing “all forms of racism”—which he must know by now is upsetting to Jewish activists, who see it as evidence that he cannot recognize the unique challenge of anti-Semitism. Corbyn added that he did not accept all the findings of the report.

That last statement sealed his political death warrant. Starmer served as Corbyn’s Brexit spokesman, and ran for the leadership on a platform of unity, promising to heal the division between the Corbynite left and the rest of the party. He was widely expected to reform Labour’s complaints procedures in light of the EHRC report and perhaps even criticize his predecessor by name. But suspending Corbyn from the party, one he has represented in Parliament since 1983, is a much more decisive—and incendiary—move.

Corbyn won the Labour leadership in 2015 on the promise he would take the party to the left, breaking with the capitalist-friendly policies and political centrism of former Prime Minister Tony Blair. Labour’s socialist faction had long been marginalized—one of Blair’s advisers once spoke about consigning it to a “sealed tomb”—and from the start, Corbyn felt attacked by the media and undermined by many of his own members of Parliament, who sat closer to the political center than Corbyn’s supporters.

As the friction grew, his long associations with fringe left-wing groups were a point of contention. A firm opponent of colonialism, he had spent years associating with activists who saw Israel as one of the evils of the modern world because of its activities in Gaza and the West Bank. In those circles, criticisms of Israeli policy too often slid into conspiracies about divided loyalties, a sinister “Jewish lobby,” and shadowy cabals of “bankers” or “Rothschilds” ruling the world. Corbyn had personally invited a Holocaust denier to Parliament and referred to members of the militant group Hamas as “friends.”

Before last year’s election, Britain’s chief rabbi went public with his fears over what a Corbyn government would mean for British Jews. One of Labour’s oldest affiliates, the Jewish Labour Movement, refused to campaign for the party. Britain’s Jewish population is tiny, so this had a negligible effect on the electoral results, but it tainted Labour’s cherished self-image as a champion of equality and anti-racism.

Starmer’s wife is Jewish, and he feels a moral, as well as strategic, imperative to tackle anti-Semitism. His first speech as leader addressed the problem head-on, and he quickly met with Jewish groups that had complained of being frozen out by Corbyn. In June, he sacked his Corbynite rival for the leadership, Rebecca Long Bailey, from his shadow cabinet for sharing an article containing an anti-Semitic conspiracy theory on social media. After several other Corbynite shadow ministers resigned on October 5 over an unrelated disagreement (a bill about undercover operations by the security services), the Labour left is now highly marginalized in Parliament again. It might not be in a “sealed tomb,” but it has gone from believing it could be on the verge of governing Britain to its present humbled and diminished state in less than a year.

How much firepower do Corbyn supporters have to aim at Starmer? The current Labour leader is no one’s idea of a charisma machine, but he has previously run a large organization, as Britain’s chief prosecutor, and is nerdishly interested in how institutions work. That has served him well as Labour leader. Since taking over, he has assembled a loyal office, installed his favored candidate in the party’s administration, and laid the ground for the decision to suspend Corbyn by declaring that the party had a “new leadership.” Nonetheless, a civil war in Labour could prove debilitating and even fatal to his chances of becoming prime minister.

As I wrote in December, denying the extent of anti-Jewish sentiment and conspiracy theories—implying that there was a “witch hunt”—had become a loyalty test on the left in Britain. Starmer has indicated that Labour has no room for anyone, no matter how senior, who contests the existence of the problem.

The question now is this: Will the rump of Corbyn’s supporters mount a coup attempt on Starmer? Or now that the pretense of “unity” is gone, could Corbyn become a king in exile? Since stepping down, the former leader, who once drew thousands to his rallies, has largely retreated to defending his record and commenting on liberation struggles abroad. Perhaps he might remember his heyday and brand himself as the leader of “True Labour” or something similar. Any new outfit would struggle to win seats under Britain’s electoral system—the experience of those who left Labour to form a new party in the last Parliament is not a happy one—but who cares? Corbyn never really believed in parliamentary democracy as a route to socialism anyway. He might feel life is more congenial as the Old Pretender, criticizing his successor from beyond his reach.

This is an arresting moment in British politics—a truly unexpected event—and a rare one in global terms, too. The U.S. is less than a week away from an election which the president is expected to lose. Yet if he does, there will be no catharsis, no reflection, no denunciation.

Starmer has shown that another way is possible. His decision is a gamble. It is the nuclear option. It is a reckoning.

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