Correction: An earlier version of this editorial included incorrect dates for Lee Kuan Yew’s tenure as Singapore’s prime minister. He held the post from 1959 to 1990. The following version has been updated.

LEE KUAN Yew was the democratic world’s favorite dictator. Over the course of half a century, the Singaporean leader, who died on March 23 at the age of 91, helped propel his island city-state from a backwater British colonial trading post to one of the world’s richest countries. His counsel was sought by a succession of U.S. presidents and many other world leaders, who valued his insights about China, capitalism and what he called “Asian values.”

High among those values was a belief in strict discipline and a disregard for democracy, which Mr. Lee claimed was not suited for developing nations. As prime minister from 1959 to 1990, he created a public administration renowned for its efficiency and lack of corruption, which became the foundation of Singapore’s economic takeoff. He steered the country through independence from Britain, a painful divorce from Malaysia and multiple wars and upheavals in Southeast Asia, while forging a community from Singapore’s ethnic mix of Chinese, Malay and Indians.

But Mr. Lee also persecuted anyone who violated his hidebound notions of public order, from gum chewers to gay people, media critics and opposition political leaders. “I had to do some nasty things, locking fellows up without trial,” he told the New York Times in 2010 . One opponent, Chia Thye Poh, was imprisoned for 23 years without charge or trial beginning in 1966. More recently, opposition party leader Chee Soon Juan was bankrupted by spurious libel suits and repeatedly jailed for offenses such as speaking in public without a permit and saying that the judiciary is not independent.

With his domestic media subservient, Mr. Lee frequently targeted Western news organizations that had the temerity to suggest that nepotism or dynastic politics might explain the installation of his son as prime minister in 2004 , or other appointments of family members to high positions. The International Herald Tribune, the Economist and Bloomberg News were among those hit with suits and forced to pay fines and print retractions.

None of this prevented several generations of U.S. and European leaders from seeking Mr. Lee’s counsel and offering glowing praise for his wisdom. Former secretary of state Henry Kissinger has said that no world leader “has taught me more ”; former British prime minister Tony Blair called him “the smartest leader I ever met.” To be sure, Mr. Lee was shrewd in judging his giant neighbor, China, and its leaders. Beijing respected him, too, and at times he helped West and East to understand each other.

Mr. Lee was, however, demonstrably unwise about democracy in Asia. While he was touting supposedly unique Asian values incompatible with liberal Western norms, Taiwan, South Korea and Indonesia became robust democracies and prospered economically. Now Singapore’s entrenched establishment is under pressure from a generation accustomed to free expression on social media. “It’s a different generation, a different society, and politics will be different,” Prime Minister (and Lee’s son) Lee Hsien Loong told The Post’s Lally Weymouth in 2013. “We have to work in a more open way.”

Arguably, Mr. Lee’s stewardship of Singapore has made it inevitable that a prosperous, globally connected society will embrace personal and political freedoms. But the country will sustain its success only if his successors abandon the dark side of his legacy.