Labour leader Jeremy Corbyn in London in 2017. (Frank Augstein/AP)
Columnist

When I was in London recently, a British friend offered effusive thanks for the United States — whenever he was feeling particularly aghast over the disarray of his country’s political institutions, he said, he just looked across the Atlantic and instantly felt much better.

Funny, I told him, I was about to say the same about Britain.

There has been a lot of talk lately about the erosion of the long-standing U.S.-British “special relationship.” Yet in one respect the countries are more tightly linked than ever before: Both are enduring a collective nervous breakdown of their political institutions.

It is only the latest symptom of the United States’ madness that President Trump just spent nearly a week making xenophobic and un-American remarks about “the Squad,” the four ultra-progressive congresswomen who also happen to be women of color. And that in consequence, the House Democratic caucus, filled with members who normally seethe at their radical colleagues, is now loyally defending the biggest thorns in its side.

Time for a soothing peek across the Atlantic, where the Conservative Party leadership election is drawing to a close. It very much looks as if Theresa May, stepping down as prime minister, will be replaced later this month by former London mayor Boris Johnson, a theatrical politician who provides hours of fun for an amazed press corps.

On Thursday, in anticipation of Johnson’s presumed victory, the House of Commons — controlled by Johnson’s Tory colleagues — voted for a measure that would prevent him from using a parliamentary maneuver to force a “no deal” Brexit come Oct. 31.

Despite the lunacy of the springtime Brexit brawl that prompted May to resign as prime minister and open the way for Johnson, the true craziness is that somehow the Conservative Party still has a leadership election worth worrying about. The party is a shambles, its reputation in tatters, but amazingly the Tories are still holding on to power, albeit with a weakening grip.

That almost defies explanation. After all, David Cameron, May’s predecessor, called the 2016 referendum on leaving the European Union, thrusting both his party and his country into the current mess. Under May’s leadership, things somehow, incredibly, got worse. After more than two years of tireless work, May failed to secure a parliamentary majority to do anything about Brexit — not to go through with it or to call it off. Now they’re about to get Johnson, which will only be a different sort of insanity.

Yet look at the alternative. Jeremy Corbyn, the Labour Party’s current leader, is an unreconstructed 1970s radical. His party has promised to nationalize private utilities and expropriate shareholders, along with raising taxes and increasing spending. And on the most important issue currently facing his country, Corbyn has been just as incapable as the Tories of sketching out a plausible, coherent path forward on Brexit.

Meanwhile, Corbyn’s amiable tolerance for anti-Semitism has gotten so bad that Labour peers in the House of Lords are considering a symbolic vote of no confidence in his leadership. British voters don’t seem any fonder: During the recent European elections, the Labour Party pulled just 14 percent of the vote.

If anyone other than Corbyn had been at the head of the Labour Party, May’s government would probably have fallen long ago. He may yet end up at Downing Street. But the only reason Labour doesn’t already have the keys is the party’s dramatic leftward lurch. In the United States, centrists fear that the Democratic Party is repeating Labour’s mistakes.

The current Democratic presidential hopefuls are generally running to the left, courting activists who argue that the party can beat Trump only by mobilizing the base. Spurned centrists complain that the progressives are guaranteeing four more years of Trump rallies and trade wars. But so far, neither party seems interested in the centrists’ increasingly dire predictions.

Which points to an even deeper parallel between Britain and the United States. Thanks to “first past the post” electoral systems, both nations have two major parties that alternate in power. In both countries, those parties are abandoning the center in favor of their fringes. And radicalism in one side breeds more radicalism in the other, in an increasingly vicious cycle.

Partisans excuse their own radicals on the grounds that, hey, the other side is worse. And they assume that because the other side has moved so far from the center, eventually the center will have to support them instead.

In fairness, one set of partisans has to be right about this. And soon enough, both Britain and the United States will find out which.

Read more:

Anne Applebaum: Boris Johnson isn’t the cause of Britain’s unseriousness. He’s the product of it.

Toby Young: Boris Johnson will be an utter disaster — unless he turns out to be Britain’s savior

Sonia Purnell: Boris Johnson is woefully unprepared to be the next prime minister

Henry Olsen: Boris Johnson may be just what Britain needs