Now and then a country needs to get slapped. England does, or rather the United Kingdom, but I say England because I really mean London. Its entire leadership class has been undone since Brexit passed, three years ago this month. They’ve been overwhelmed, not equal to the moment.

They are like the hysterical blonde in 1940s and ‘50s movies. Something scary would happen, the monster was coming, and she’d start to scream and sob. Then another character, usually a man, would slap her hard across the face. In the shock of it she’d take hold of herself. I’m fairly certain this trope had to do with how directors saw their wives.

Anyway, London since Brexit has been the hysterical blonde. The British people passed Brexit in a national referendum many had requested for decades. It wasn’t close — it won by a 3.8-point margin. Turnout was huge, 72% of eligible voters. Then-Prime Minister David Cameron, who opposed Brexit but called the referendum in a stupendous and foolish bet that his people saw things as he did, was forced to step down. Theresa May, who’d opposed Brexit but with less focus and commitment, rose from the debris and had a good start. “Brexit means Brexit,” she said. And then she too misread the situation, on the ground and in Parliament. The argument didn’t end. The European Union did what everyone knew it would do and tried to stop the jailbreak. Everything got drawn out and dragged down. The whole political class floundered under the strain.

If leaving the EU was a radical decision, it was deliberately and consciously so: For six weeks the question consumed the nation, and a decision was made.

Is it not obvious what must be done? This matter has to be resolved. A great nation can’t function cut in two, with half the nation at the other half’s throats. It can’t go forward in history that way; it must be one thing or the other, as Lincoln said.

The people asked for Brexit. The government has to deliver it. You can’t insult the very idea of democracy and say, Oh, well, this is hard, so we’ll have a do-over on the vote and hope the people will deliver a different outcome. You have to accept the result and forge ahead.

Make Brexit happen, make the break. Move forward as the people instructed. If you can get EU cooperation, get it. If not, stop pleading and dragging it out. Settle this. If it works it will be apparent within a few years, so hold a parade. If it doesn’t, public opinion on a second referendum will be different.

But stop whingeing. You were hired to lead the people. If you’re not talented enough to do that, you can at least follow them.

In connection to this, the Conservative Party leadership race to replace Mrs. May began this week. Boris Johnson, the former foreign secretary and London mayor, made the case for his candidacy. “After three years and two missed deadlines,” he said, “we must leave the EU on Oct. 31.” He hopes for a deal, but the next government should prepare “vigorously and seriously for no deal.” “Brexit delay means defeat,” Mr. Johnson contends. “The paradox is that we have not allayed the divisions in our society by failing to deliver the outcome… . We made them worse.”

He’s right. He is also probably going to win. The problem is that he is famously slippery and no one ever knows if they can trust his word. Ken Clark, the Conservative former chancellor of the Exchequer, told the Guardian that Mr. Johnson “doesn’t have any policies, certainly none that are consistent from day to day,” and added: “I don’t actually think he knows what he would do to get us out of the Brexit crisis.”

Mr. Johnson is not an especially good man. His greatest fans admit he is dishonest, even for a politician. But he has wit, verve and intellectual quickness. He has a showman’s love of comedy. A friend who’s a historian of the royal family mentioned as a reason to support him that Queen Elizabeth II has been holding weekly audiences with her prime ministers since 1952: “After all these years she deserves a laugh.” She does.

But the reason Mr. Johnson will likely win is that he is the only serious candidate who understands the politics of the situation—that Brexit simply must be put through, finally and soon. On top of that he’s a compelling figure, with an appreciation of and talent for the show businesses of politics.

He’s never seemed to believe in much beyond his right to rise to the top; he is a born cynic. When Brexit, whose cause he led, surprisingly passed, he suddenly was responsible for a difficult situation. In response he fled for the hills and was incommunicado for days. But his cynicism, perversely, might make him a good match for the EU, which doesn’t seem to believe in much beyond its right to run things whether its constituent nations like it or not. Mrs. May is a very decent person, and she was outmatched. The great thing about cynics is that they tend to do the practical and obvious thing, and the obvious thing to do now is push the EU hard, then stop.

Mr. Johnson’s admirers have the grating habit of comparing him to Winston Churchill, a flawed outsider with imperfect judgment but the right man for 1939. But Churchill was an authentic genius who wrote a masterpiece of the English language while drunk and went to war hung over. He was a gigantic character. Boris Johnson is merely a big one, and a showman. No one knows what he will achieve, but he surely knows he must deliver. My friend the historian believes Mr. Johnson can reinvigorate Britain, “which has lost confidence in itself after spending the last three years on bended knee.”

The second country that needs a slap this week is China. It needs to be told no — colorfully, vividly, and in a great chorus. It needs to know the upset it is causing in trying to muscle the people of Hong Kong with extradition moves is not worth the gain — that it will ruffle things in a way that is not good for China. The world admires Hong Kong’s freedoms, bustle and success. China needs to be made to understand it damages its standing and stature by bullying that little city. It would be good if it saw it is causing a great clamor.

World, be roused. Push back through word, opinion and argument. Let Beijing know there’s a price for its moves.

Chinese rulers the past few years have seemed quite full of themselves. They pride themselves on taking the long view of history, and on their heavy competence, their ability to hold their balance amid domestic pressures and internal contradictions. They are willing to sacrifice in the day-to-day to achieve long-term objectives. They’ve enjoyed three decades of economic growth, moved forward in telecom, mining, energy, manufacturing. High military spending, military modernization, Huawei, 5G. They’ve been rising for decades, all the while giving the impression that they see the West as being composed of distracted materialists with their faces in screens.

This would be a good time to make a mighty roar, and surprise them with some energy and feeling.

Reprinted by permission from peggynoonan.com.