When Macau, the Portuguese colony turned Chinese gambling hub, got a new chief executive in October, the vote by an electoral committee was unanimous. He ran unopposed. No one took to the streets in protest.

When young activists applied for permission to demonstrate in support of the protest movement in nearby Hong Kong, the authorities said no -four times. When a few dozen showed up anyway in Macau’s historic center in August, the police arrested seven of them.

Macau today, like Hong Kong, is a political experiment that began in the late 1990s, when China reclaimed both territories from Western colonial powers and promised that civil liberties could coexist with its brand of authoritarian rule. Now, as Hong Kong’s political unrest continues, China’s ruling Communist Party has become increasingly explicit about how much it will tolerate under that formula -and holds Macau up as a shining example of obedience.

“The most important thing is to implement and safeguard the central government’s full control,” Li Zhanshu, the third highest-ranking official in China, who presides over policy for both territories, said in a speech about Macau in Beijing this month.

Compared to Hong Kong, Macau has more readily accepted Beijing’s ultimate authority on matters of national policy under the “one country, two systems” formula applied to both of them. And for the most part, the city’s 670,000 residents have gone along with it, either co-opted or coerced by the mainland.

“After 20 years in Macau, it is difficult to find the clear lines between the two systems,” said Sou Ka Hou, one of 33 deputies in Macau’s Legislative Assembly and, at 28, a leader of a new generation of democratic opposition.

China’s leader, Xi Jinping, arrived in Macau on Wednesday for a three-day visit to mark the 20th anniversary of the territory’s “return to the motherland” in 1999, after more than four centuries of Portuguese rule. His visit, touted in China’s state media, carries the implicit message that satrapy has its rewards.

“As we used to say, good boys get candy,” said Larry So Man-yum, a retired professor of social work at Macau Polytechnic Institute who is now a gambling addiction counselor. “Macau is a good boy.”

For China’s leaders, Macau offers the answer to seditious obstinacy in Hong Kong, 40 miles to the east, where protests that began in June over a bill that would have allowed extradition to the mainland have evolved into a campaign against police violence and the Communist Party’s steady encroachment on the city’s liberties.

In Macau, more than half of the population was born on the mainland; millions more come to gamble in the city’s casinos, making them a driver of the economy. Government buildings all fly the Chinese flag. Schools use the mainland’s textbooks. No one boos the Chinese national anthem, as protesters regularly do in Hong Kong.

Most important, Macau’s political leaders have adopted laws that curb dissent, including one in 2009 that made subversion against the Chinese state a crime. In Hong Kong, similar legislation was derailed by protests in 2003 but remains an overriding priority for the party.

Mr. Sou himself was convicted of participating in a protest last year against the Macau Foundation, a government organization, over a $14 million donation it made to a Chinese university. He was stripped of his legislative duties -a first since the handover -and only later reinstated to his seat.

Mr. Sou, who rose to prominence as a leader of a civic group, is one of the few lawmakers in the city who still presses for universal suffrage, one of the key demands of Hong Kong’s protesters. He argues that Beijing has slowly chipped away at the “high degree of autonomy” it promised Macau.

In September, Macau’s highest court rejected an appeal to allow a number of protests to take place, including one against the Hong Kong police. The court ruled that such a demonstration was unwarranted because none of the actions taken by Hong Kong’s police amounted to torture or brutality - an echo of the Chinese government’s argument.

One of the people who tried to organize that rally, Jason Chao, said the ruling effectively meant that any “demonstration or an assembly about an opinion not officially recognized by the government” could be banned.

As Hong Kong has seethed, the authorities in Macau have stepped up efforts to quash any hint of dissent, fearing that their neighbor’s upheaval could spread.

As the Friday anniversary of the handover has approached, officials have denied entry to a number of Hong Kong residents, journalists and foreigners. Two leaders of the American Chamber of Commerce in Hong Kong were turned away as they tried to enter for an annual ball put on by the chamber’s Macau branch.

On the mainland, the anniversary has occasioned tributes to Macau’s transformation under “one country, two systems.” The state television network, CCTV, broadcast a series of glowing documentaries. Air China’s in-flight magazine devoted 50 pages to it.

Macau, a cluster of islands and reclaimed land totaling just 12 square miles, was the first foreign settlement in China. The Portuguese occupied it in 1557, nearly three centuries before Britain took control of Hong Kong.

Twenty years after its return to China, it retains a mixture of East and West in its cuisine and in its architecture, which has won it a UNESCO listing as a World Heritage Site. It has its own judiciary and its own currency, the pataca. Portuguese remains an official language, visible on street signs and storefronts, even if fewer and fewer residents speak it.

It enjoys liberties that scarcely exist on the mainland today. “If we did not have freedom of speech, I could not give you an interview today,” said Tung Chih Lin, a lecturer in the School of Public Administration at the Macau Polytechnic Institute.

And it has long been the more pliant of the two former colonies under Chinese rule.

The reasons for that, according to residents and historians, have to do with the different political cultures of the Portuguese and British colonial governments, and how each handled the handover to Chinese authority.

When reunification approached, Portugal granted citizenship to anyone born in Macau before 1982 and their relatives. Those who balked at Chinese rule could leave for Portugal, or another European Union country. But in Hong Kong, residents received a special British passport that stopped short of citizenship, which has made resistance to Beijing an existential fight.

Macau is also different because it is the only place in China where gambling is legal -and that delivers economic benefits.

An elevated light rail system that opened last week glides from the airport past the most famous global brands in gambling: the Sands, MGM, Wynn, the Venetian. Macau became the world’s biggest gambling center in 2006, surpassing Las Vegas, several years after the authorities expanded the number of casino licenses.

The industry now provides 87 percent of Macau’s annual budget and jobs for nearly 1 in 12 residents, according to the latest official figures. Still more people work in hotels, restaurants and other businesses that cater to visitors, the vast majority of whom are from the mainland. Since 2008, the government has also wooed the population with yearly cash subsidies, which this year totaled the equivalent of $1,246 per person.

“Macau people are overly reliant on the established economic order,” said Mr. Chao, the rights campaigner, who has moved to London. “Going against China means going against their livelihood.”

Gambling is prone to economic cycles, though, and in Macau it is also vulnerable to anti-corruption campaigns in China that target high-rolling officials. Casinos have struggled in recent months, almost certainly because the tumult in Hong Kong has cut into the number of visitors.

During his visit, Mr. Xi is expected to announce new measures to knit Macau further into an ambitious project called the Greater Bay Area, meant to build closer links between the major cities where the Pearl River meets the South China Sea.

The project calls for Macau to be the region’s hub for tourism and entertainment, including attractions beyond gambling, like the annual Macau Grand Prix and the International Film Festival and Awards Macau.

That festival’s fourth installment, held last week, drew an international A-list of celebrities, including the French actress Juliette Binoche — who, when asked, said she would not subject herself to censorship for the sake of making a film in China.

“I always have compassion for the audience who cannot really express themselves here,” she said.

For ordinary Macanese, such concerns can seem remote, even abstract. “Many people here do not understand the importance of the universal suffrage,” said Mr. Sou, the legislator. “They only concern themselves with the life issues that happen in front of their eyes.”

He warned, however, that without more democracy, Macau would lose what makes it unique. “We will just become another Chinese city,” he said.