“If you believe you’re a citizen of the world, you’re a citizen of nowhere. You don’t understand what the very word ‘citizenship’ means.”

Those were the key words of a speech by Prime Minister Theresa May of Britain, at the Conservative Party conference in Birmingham last week. My response — as a fully paid-up member of the rootless cosmopolitan class — was: Ooh la la!

Welcome to the new class war, Brexit edition.

On one side, the citizens of the world — the Weltbürger — who are only citizens in the sense that Orson Welles’s Citizen Kane was a citizen. We have at least two passports. We speak at least three languages. And we have at least four homes, not one of them in the town where we were born.

Last Monday night we saw the first of three showdowns between a terrible complicator — Hillary Clinton — and a terrible simplifier — Donald Trump.

Slumped in the Democratic corner, her haggard visage being fanned by anxious trainers, is Clinton, candidate of the status quo. Impatiently bouncing off the ropes on the other side of the ring is the overweight, orange-featured personification of very, very risky change. The status quo’s margin of advantage suddenly looks much smaller than anyone thought in the dog days of summer.

We urge the next president to establish a White House Council of Historical Advisers. Historians made similar recommendations to Presidents Carter and Reagan during their administrations, but nothing ever came of these proposals. Operationally, the Council of Historical Advisers would mirror the Council of Economic Advisers, established after World War II. A chair and two additional members would be appointed by the president to full-time positions, and respond to assignments from him or her. They would be supported by a small professional staff and would be part of the Executive Office of the President.

In his prophetic 2012 book, Coming Apart, my friend Charles Murray identified the stark social division that is defining this year’s presidential election.

What comedy! What a circus! Melania Trump’s speech was ripped off from one of Michelle Obama’s. Donald Trump’s affectionate, er, grope of his daughter Ivanka was weirdly inappropriate. His air kiss of vice presidential pick Mike Pence was an air miss. And the new Republican rock anthem, “Make America Great Again,” appeared to have been written by the creators of “South Park.’’

This is a representative sample of the things said by members of the American elite about last week’s Republican National Convention in Cleveland. Ignore it all. Their sneering is just irrelevant noise. The signal was what mattered and, though it was loud (and at times monotonous), it was also very clear.

To understand what has just happened in Britain, mystified Americans are advised to read the novels of Anthony Trollope. I especially recommend “Framley Parsonage.’’ There is a wonderful parody there of a Victorian change of government, which dashes the political ambitions of the unscrupulous Harold Smith, briefly elevated to the Petty Bag Office.

Harold Smith has been brought into the Cabinet by Lord Brock, the prime minister, but swiftly falls foul of his jealous friend Mr. Supplehouse, who savages him in an article in the “Jupiter.’’ Then, with breathtaking suddenness, the Brock government is overthrown.

“Now is the end! Perish the world!” In a hilarious 1961 sketch, the “Beyond the Fringe’’ team played a millenarian sect, led to a mountain top by Peter Cook to await the end of the world. After protracted discussions about the precise form the apocalypse will take —“Will this wind be so mighty as to lay low the mountains of the earth?” “No, it will not be quite as mighty as that”—there is a long and expectant silence.

A number of years ago the British apparel chain “French Connection” unveiled a daring and eye-catching new marketing slogan: the initials FCUK. This seems like the mot juste for the British disconnection that happened last week.

Speaking on the BBC, the UKIP leader Nigel Farage called the Brexit result a victory for “ordinary people, decent people.” This offered a revealing insight into the way Farage regards the 48 percent of people who voted to remain inside the EU. It was certainly a defeat for Prime Minister David Cameron, Chancellor George Osborne, and other members of the government who remained loyal to them. It was also a resounding defeat for bookmakers, political scientists, most media pundits, most pollsters, and the vast majority of investors. Among these were the same experts who failed to foresee that Donald Trump would win the Republican nomination.

No man is an island, as John Donne said. Every murder changes the world a bit. I suspect the murder of Jo Cox, the young British member of Parliament killed in Birstall last Thursday, was the sort that changes the world a lot. I wish I could say the same about the murders of the 49 people who lost their lives in Orlando a week ago.