I used to say that Deng Xiaoping should receive the Milton Friedman Prize for Advancing Liberty because he had freed more people than anyone in history. His latest successor as China’s leader, Xi Jinping, who has just become China’s unchallenged dictator, seems bent on reversing that achievement.

(Of course, Deng couldn’t actually have received the prize because he had died before the prize was created, and also because his rough methods both before and after his ascension to supreme power would have disqualified him.)

The victory of the Chinese Communist Party in 1949 and the subsequent rule of Mao Zedong created a one-party tyranny and desperate poverty in China. The “Great Leap Forward” led to mass starvation. The Cultural Revolution unleashed “an extended paroxysm of revolutionary madness” in which “tens of millions of innocent victims were persecuted, professionally ruined, mentally deranged, physically maimed and even killed.” Estimates of the number of unnatural deaths during Mao’s tenure range from 15 million to 80 million.

Which was no surprise. The party was formed in 1921 with an official ideology of Marxism‐​Leninism. On July 1, 1949, as the Communist armies neared victory, party leader Mao Zedong made an important speech titled, “On the People’s Democratic Dictatorship.” Instead of life, liberty, and the pursuit of happiness, Mao spoke of “the extinction of classes, state power and parties,” of “a socialist and communist society,” of the nationalization of private enterprise and the socialization of agriculture, of a “great and splendid socialist state” in Russia, and especially of “a powerful state apparatus” in the hands of a “people’s democratic dictatorship.” That was the CCP’s founding vision, which it carried out.

After Mao’s death Deng Xiaoping, a victim of the Cultural Revolution, came to power. He had learned something from the 30 years of calamity. He began to implement policies he called “socialism with Chinese characteristics,” which looked a lot like freer markets: decollectivization and the “responsibility system” in agriculture, privatization of enterprises, international trade, liberalization of residency requirements. And China started emerging from poverty and tyranny.

The changes that Deng wrought are the greatest story in the world—more than a billion people brought from totalitarianism to a largely capitalist economic system. According to the Economic Freedom of the World report, China’s economy was significantly freed. China remains only 116^th in the world in economic freedom (out of 165 countries), but compared to communism that’s a big step up.

Thanks to the economy’s liberalization China’s GDP per capita (in constant dollars) has risen from $326 at the time of Mao’s death to more than $11,000. When the Cato Institute held conferences in Shanghai in 1988 and 1997, it seemed that China was becoming more prosperous and even somewhat more open to economic and political discussion. New York Times reporter Howard W. French wrote in 2008, “China’s example shows what kinds of remarkable results can follow when governments stop committing colossal blunders and grossly shackling or preying upon their own people.”

And then along came Xi, who became the leader of the Communist Party and the state in 2012. From that point on, Xi began to crack down on independent thought, independent businesses and businessmen, and state and party officials who demonstrated any independence. Xi has become more authoritarian, and has concentrated more power in his own person than any ruler since Mao. Some say China is becoming “the perfect dictatorship.” As Jude Blanchette and Evan S. Medeiros wrote, Xi Jinping moved not only to make himself and the party more powerful but also to make the party more ideological. New guidelines for party membership in 2014 “required all individuals entering the CCP to ‘possess a belief in Marxism and in socialism with Chinese characteristics’ as a basic criterion. So too must members ‘place political standards above all else,’ which entails priority to Party commands and ideology.”

The just-completed Communist Party Congress has confirmed Xi’s absolute rule. He has filled the upper ranks of party leadership with his own loyalists. China is richer and more powerful than ever, and Xi rules more absolutely than any Chinese leader since Mao. But he cannot be entirely happy with what he surveys. China’s reported GDP growth rate has fallen off dramatically, and a new study says that dictatorships including China have persistently reported higher rates than they actually achieved. Greg Ip writes in the Wall Street Journal:

Under the benign neglect of Mr. Jiang and Hu Jintao, leader from 2003 to 2013, entrepreneurialism and innovation flourished. China’s most impressive tech companies were founded in this period….

Mr. Xi has reined many of them in, singling out the most successful business leaders for harassment and prosecution, kneecapping their businesses and insisting all private companies adhere to the Communist Party’s priorities. Money still pours into Chinese startups, but the odds one will be the next Alibaba have diminished.

Tech leaders can’t leave China, but “they are telling their adult children to make their careers elsewhere,” said Sebastian Mallaby, who profiled China’s venture-capital industry in his book “The Power Law: Venture Capital and the Making of the New Future.”

Globally, more than a billion people have emerged from extreme poverty in the past 30 years, and the lion’s share of that number were in China. But with increased political control over the economy, that progress is not likely to continue. Xi’s lust for power is in direct conflict with continuing economic growth.

A scholar wrote in the Washington Post this week that the media should stop calling Xi the president of China. Yes, I thought when I saw the headline, he’s not an elected leader like most presidents; let’s call him something more accurate. But the scholar just wanted journalists to call him “general secretary,” the formal title that identifies his real power. Better, I’d say, to call him “dictator,” as journalists typically referred to Chilean leader Augusto Pinochet. “Chinese dictator Xi Jinping today ordered a crackdown on Hong Kong.” That would convey reality better than “president.”

Liberalism is the most revolutionary idea in world history. It has literally made the lives of billions of people not just freer and more comfortable but possible. Yet somehow dissatisfied people, and men (almost always men) bent on power, keep turning to alternative ideologies. Liberalism has faced challenges from monarchy, theocracy, fascism, communism, military dictatorship, “Asian values,” central planning, and more. Still countries find peace and prosperity in proportion to their embrace of liberal values and institutions.

China’s economic reforms—liberal reforms—since 1976 have dramatically reduced poverty, increased economic growth, and made Chinese companies some of the world’s largest. But if Xi moves the country further from liberalism, he will choke off its growth. And perhaps go down in Chinese history as the worst leader since Mao.