LONDON — I moved to London from Istanbul over a decade ago. As a novelist put on trial in Turkey for writing fiction, I longed for freedom of speech, and wanted to live in a place with a strong liberal democracy and stable democratic institutions. Back then, Britons were calm when they talked politics. Even when they disagreed, they seemed to remain controlled, and norms prevailed. In the post-Brexit era, that distinctive British calmness and sense of continuity is no more. Politics has become divisive, aggressive, emotionally charged. The dominant motto is to disrupt, dismantle and defeat. As my adopted country becomes increasingly polarized and drifts further away from Europe, I find myself seized by a strange sense of déjà vu: Some of what I see in the U.K. today reminds me of what I’ve seen happen in Turkey.

Democracy is far more fragile than generally assumed. It is a delicate ecosystem of checks and balances. Referendums and elections, however vital, are not enough to maintain a democracy. Let us not forget that Russia has elections. Turkey has elections. They are not democracies. In addition to the ballot box, democracy is about the rule of law, separation of powers, media freedoms, academic independence, human rights, women's rights and minority rights.

The political trajectory of Turkey holds important lessons for progressive-minded citizens across the world. The country has gone backward — at first gradually, and then with astonishing speed. Its fledgling democracy fell to pieces under tides of populist nationalism and populist authoritarianism. The government, guided by President Recep Tayyip Erdoğan, came to power with promises of reform, freedoms and pluralism, but delivered the exact opposite. Media diversity was crushed, academics and journalists were arrested, civil society was stifled from above. Turkey, once a resolute candidate for European Union membership, catapulted itself onto the periphery of Europe.

It all began with words: a toxic language of divisiveness, us and them, the “people” versus “the establishment.” Erdoğan’s Justice and Development Party portrayed itself as the sole representative of the people. “We are the people,” said Erdoğan. “Who are you?” Criticizing the government became tantamount to criticizing the people. All opposition was stymied in the name of the people.

A similarly toxic rhetoric is taking hold in countries where populism is on the rise. In Hungary, Prime Minister Viktor Orbán depicts any criticism directed at his government as an attack against the people, an attack against Hungary. The right-wing populist Freedom Party in Austria claims to be the voice of the people, accusing opponents of being the voice of high society. In Poland, the leader of the conservative ruling party, Jarosław Kaczyński has called opposition members "traitors."

Once, political scientists assumed that some European countries were historically inoculated against populism. Today, we have seen that’s not the case.

Such inflammatory language is neither coincidental nor accidental. It lies at the heart of the populist strategy for electoral gain. Today in the U.K., hardcore Brexiteers call people who disagree with them “traitors” and warn of “betrayal.” Prime Minister Boris Johnson has been repeatedly criticized for naming a bill that would stop a no-deal Brexit as the “surrender bill” or “capitulation.”

This kind of rhetoric has a damaging effect that goes beyond pure politics. When nationalism escalates, so does sexism and misogyny. Female opposition MPs have become easy targets. They receive death threats and constant abuse, and last month Labour MP Paula Sherriff asked the prime minister to tone down his language, telling the parliament that trolls, clearly emboldened by the new political climate, were echoing his words. Johnson’s reply was that he had never heard such “humbug” in his life, though he later said it was a "misunderstanding."

Suddenly, politics has become a war zone and people’s lives are in danger. Martial metaphors of destruction and death are used abundantly. Johnson says, "I'd rather be dead in a ditch than agree to a Brexit extension." Meanwhile, benefiting from the chaos, Brexit Party leader Nigel Farage tells centrist parties, “Get Brexit done or die!”

There is no doubt that the U.K. is undergoing tough and extraordinary times. European capitals are watching with concern. But it would be a historic mistake on the part of European intellectuals to forget that the U.K. is not alone in this. In truth, no country is immune to the rise of populist nationalism and tribalism. Once, political scientists assumed that some European countries were historically inoculated against such disruption. Today, from Germany to Sweden, Austria and Spain, we have seen that’s not the case.

The waves of nativism that are shaking the U.K. today are also waves that are ready to disrupt different parts of Europe tomorrow. It’s important that we remember, as world citizens, that we are all in this mess together. What happens in one country has a direct impact on what happens elsewhere, and the solutions to today's problems — whether climate change or terrorism or the dark side of technology — can only be achieved by working together. Democracies wither away when countries feel isolated.

Elif Shafak is a novelist, public speaker and political scientist. She is the author of 17 books, 11 of them novels, including “10 Minutes 38 Seconds in This Strange World” (Penguin, 2019), which was shortlisted for the 2019 Booker Prize.