Early in his career, Turkish President Recep Tayyip Erdogan made a remark that sums up the tragedy of modern Turkey. “Democracy is like a train,” the then-Istanbul mayor said. “You get off once you have reached your destination.”

Erdogan’s train seems to have arrived. In last Sunday’s referendum, a razor-thin majority granted him massive new powers in a vote rife with irregularities. As Erdogan cements his rule in his 1,150-room palace, he’s dashed the dream that he’d create the first modern democracy in a mainly Muslim country.

President Donald Trump quickly called to congratulate Erdogan and may soon invite him to the White House. Yet Turkey’s reliability as a NATO ally is under severe question and Ankara has become a liability in fighting the Islamic State in Syria.

The hopes that Erdogan’s AK Party would morph into a Muslim version of Europe’s conservative Christian Democratic parties was always unrealistic. His early prime ministerial achievements were impressive, however, boosting the economy and starting peace talks with Kurdish rebels. Turkey now has a 95 percent literacy rate, the highest in the Muslim world.

But, having moved from prime minister to president — until now, a largely symbolic post — Erdogan’s megalomania took over. He set out to emulate Attaturk, the founder of modern Turkey, whose authoritarian rule built a secular state from the ruins of the Ottoman Empire.

“Erdogan is following the Attaturk model, using state power to shape country and society in his own image,” says Soner Cagaptay, author of “The New Sultan: Erdogan and the Crisis of Modern Turkey.” “He doesn’t share Attaturk’s (secular) values, just his methods. He wants to use state power and education to make the country religious, conservative and Middle Eastern.”

But the country is far more complex than that: It is a mix of seculars, moderate and pious Muslims, Kurds, Alavis (a Shiite sect), Christians, and Europe-oriented businessmen. That’s why he only won 51 percent of the ballots.

“Half the country loves him and half loathes him,” Cagaptay said at the Washington Institute for Near East Policy in Washington. “He exacerbates the divide.”

And that divide was growing long before the election. In recent years, the Turkish president had been cracking down on peaceful demonstrators and jailing journalists. But, with an eye on the votes of nationalist Turks, he restarted a brutal war with Kurdish rebels.

He also used a mysterious coup attempt last year to conduct massive purges at home, not just of the alleged plotters, but of civil society and the peaceful HDP Kurdish opposition party. He blamed the coup on Fetullah Gulen, a Turkish cleric living in exile in the Poconos region of Pennsylvania, whose extradition he demands.

As many as 71,000 people have reportedly been detained and 41,000 formally arrested, while tens of thousands of academics, judges and police have been fired and many universities, schools and media outlets shuttered.

Experts debate whether Erdogan is an authoritarian or an Islamist. Cagaptay told me he’s both.

“He will try to Islamicize politics and society,” the author said. But moving in that direction would require Erdogan to keep repressing Turkey’s democracy, which would undermine its stability and economy. An advanced economy requires an open society with ethnic and religious tolerance.

In Turkey, Cagaptay says, that means “freedom for religion for the religious half — and freedom from religion for the secular half.” But Erdogan seems wholly oriented toward his pious followers.

However, the news is not all bad. The fact that nearly half of Turkey’s voters rejected the referendum, despite severe repression, shows that the country’s civil society remains vibrant. This puts some restraints on Erdogan.

Moreover, he has created huge problems with his neighbors. His help to Sunni Islamists fighting the Syrian regime has boomeranged, creating a terrorist problem at home and annoying Moscow. Cagaptay says Erdogan needs help from NATO to offset pressures from Russia, which is still an enemy despite surface reconciliation.

So, rather than flatter the Turkish sultan or bow to demands for Gulen’s swift extradition, Trump should insist that the Turkish leader stop undermining the Syrian Kurds, who are America’s best allies against the Islamic State. He should urge Erdogan to restart peace talks with the Kurds and avoid civil war.

“The time for the Attaturk model has passed,” says Cagaptay. “It won’t work.”

That may be too much to discuss over chocolate cake at Mar-a-Lago, but Trump’s affinity for dictators should be put on hold if he invites Erdogan to his home.

Trudy Rubin is a columnist with the Philadelphia Inquirer.