Late last month, foreign officials in army regalia toasted their hosts in Naypyidaw, the bunkered capital built by Myanmar’s military. Ice clinked in frosted glasses. A lavish spread had been laid out for the foreign dignitaries in honor of Myanmar’s Armed Forces Day.

That very day, the military, which had seized power on Feb. 1, gunned down more than 100 of its own citizens. Far from publicly condemning the brutality, the military representatives from neighboring countries — India, China, Thailand and Vietnam among them — posed grinning with the generals, legitimizing their putsch.

The coup in Myanmar feels like a relic of a Southeast Asian past, when men in uniform roamed a vast dictators’ playground. But it also brings home how a region once celebrated for its transformative “people power” revolutions — against Suharto of Indonesia and Ferdinand Marcos of the Philippines — has been sliding back into autocracy.

From Cambodia and the Philippines to Malaysia and Thailand, democracy is languishing. Electoral politics and civil liberties have eroded. Obedient judiciaries have hobbled opposition forces. Entire political classes are in exile or in prison. Independent media are being silenced by leaders who want only one voice heard: their own.

alliance of democracies.” With China and Russia involved, the United Nations Security Council has done nothing to punish Myanmar’s generals.

Covid-19 with them.

A scheduled special meeting on Myanmar by the Association of Southeast Asian Nations offers little hope of action. That consensus-driven group avoids delving into members’ internal affairs. Earlier negotiations among regional foreign ministers didn’t result in a single policy that would deter Myanmar’s coup-makers.

Besides, many of the region’s leaders have no wish to uphold democratic ideals. They have used the courts to silence their critics and met protest movements with force.

But if authoritarians are looking out for one another, so, too, are protesters. In Thailand, students have stood up to a government born of a coup, using a three-fingered salute from the “Hunger Games” films to express defiance. The same gesture was adopted after the putsch in Myanmar, the leitmotif of a protest movement millions strong.

its first commoner president, and Malaysia would shunt aside a governing party bloated by decades of graft and patronage. Thailand’s generals had managed to go years without a coup. Even in Vietnam, the Communist leadership was pushing forward with liberalization.

The most significant transformation seemed to be in Myanmar. The military had led the country since a 1962 coup, driving it into penury. In 2015, the generals struck a power-sharing agreement with a civilian leadership fronted by Daw Aung San Suu Kyi, the Nobel laureate who spent 15 years under house arrest. President Barack Obama went to Myanmar to sanctify the start of a peaceful political transition.

Now Ms. Aung San Suu Kyi is again locked in her villa, facing possible life imprisonment. Her supporters have been arrested and tormented. Soldiers picked up one of Ms. Aung San Suu Kyi’s followers and burned a tattoo of her face off his arm.

Much of the rest of Southeast Asia is in full-fledged democratic retreat. The leader of Thailand’s last coup, Prayuth Chan-ocha, is still the prime minister. His government has charged dozens of student protesters, some in their teens, with obscure crimes that can carry long sentences. Thai dissidents in exile have turned up dead.

After a brief interlude out of government, Malaysia’s old establishment is back in power, including people associated with one of the largest heists of state funds the world has seen in a generation. Vietnam’s crackdown on dissent is in high gear. In Cambodia, Hun Sen, Asia’s longest-ruling leader, has dismantled all opposition and set in place the makings of a family political dynasty.

President Rodrigo Duterte of the Philippines may enjoy enduring popularity, but he has presided over thousands of extrajudicial killings. He has also cozied up to China, presenting it as a more constant friend than the United States, which once colonized the Philippines.