We called it the Yonsei Beach Club. It convened the last time South Koreans exploded in protest and forced a government to capitulate, in 1987, when a small band of reporters and photographers would assemble to chronicle the daily demonstrations by students at Yonsei University in Seoul.  Then as now, mass protest was a powerful weapon deployed by enraged citizens who felt they had nowhere else to turn but the streets. Thirty years later, it’s clear how far Korean democracy has advanced. Then, South Korea was a dictatorship, protests were outlawed and the threat of torture, imprisonment and martial law ever-present.  The emblem of the Beach Club was a gas mask, because the throngs of riot police in Darth Vader masks lobbed tear gas canisters at students whose weapons were moral force, rocks and homemade firebombs.  Students have long been at the vanguard of South Korea’s robust history of protest, drawing on deep-rooted Confucian traditions that elevated scholars as guardians of morality. They helped topple a government in 1960 and rebelled in the southern city of Kwangju in 1980, only to be massacred by a military junta led by Chun Doo-hwan, who later made himself president.  The death under torture of a 21-year-old student, Park Jong-chul, in January 1987 helped set off the wave of demonstrations against Mr. Chun’s rule. South Korea’s dictators had offered economic growth and political repression; its people were clamoring for more.  By the spring, the demonstrations at Yonsei had become a daily ritual. The students would assemble, tying kerchiefs around their mouths; the police would pounce; and the tear gas would eventually drive the protesters back. Yonsei produced its own martyr, 21-year-old Lee Han-yol, who died after a tear-gas canister hit him in the head.  Gradually, the protests spilled into downtown Seoul and across the country in a rhythm both violent and predictable.  The morning would dawn, with spent tear gas canisters and shards of rocks littering the streets, the acrid fumes still stinging skin and burning lungs.  The riot police would muster near the police stations, young and vulnerable without their threatening masks, drinking tea and wiping the sweat from their foreheads. Young goons known as “skeleton troops,” trained in martial arts and feared for the brutal beatings they inflicted on protesters, would mass.  But in the end they were no match for the tens of thousands of Koreans who set fear aside and confronted the police.  I saw an older woman, hair neatly coifed, beat a policeman with her handbag. A young father hoisted his little girl on his shoulder, carefully affixing a surgical mask to her face, an imperfect shield from the gas. A student in Kwangju bit his finger and wrote protest slogans in his own blood.  Ordinary citizens broke up sidewalk tiles and handed them to students to hurl at the riot police. Office workers, in the past too frightened to risk their jobs, came out at night and honked horns in solidarity. People threw water from rooftops to try to douse the gas.  It is hard to overstate the repression and fear. The cat-and-mouse game between police and protesters would continue into the night. With nightly propaganda airing on television, before cellphones or the web, truth was elusive and rumors flew.  One night the lights at the hotel went out, and a few of us ran out into the street, convinced that martial law had been imposed — only to find that a nearby Christmas display had caused a blackout.  In a scene still indelible after so many years, I sat in a courtroom as the torturers of the young student went on trial. It was just a week or so since the protests had forced the government to yield. Months before, the police had crushed the student’s neck against the side of a bathtub as they repeatedly pushed him under water.  Protesters took to the streets of South Korea's capital on Saturday to call for the resignation of President Park Geun-hye, a day after Parliament voted to impeach her.  At the trial, his father lunged at the three policemen, small and scared now, protected by more than 50 guards. Screams broke out and a purse flew through the air at the judges as the light sentence was read. Women whose sons were still in jail stormed the bus carrying the policemen, throwing bottles against the windows. Plainclothes police shoved the four of them onto the concrete, where they lay unconscious.  By contrast, the protests this year have been peaceful, allowed to proceed unimpeded by the strong arm of the government. South Korea has come far, but as these last months showed, it is still an imperfect democracy.  Laws are still on the books that can be used as tools to stifle dissent. South Korea remains shadowed by legitimate fears of North Korean aggression and espionage, but those were and are exploited by the government.  A wide-ranging national security law was used 30 years ago as a pretext for repression; by contrast, President Park Geun-hye, whose impeachment was backed by legislators on Friday, disbanded a left-wing party and arrested its leaders under the auspices of the law.  In the 1980s, the Korean Central Intelligence Agency had plants in every government office. Those appear to be gone, but its successor agency, the National Intelligence Service, still keeps tabs on government agencies and was accused of launching smear campaigns against Ms. Park’s opponents during her campaign in 2012.  Ms. Park used South Korea’s laws criminalizing defamation to charge and imprison government critics and the press. Any South Korean president retains control of police, prosecutors and tax collectors. Endemic corruption is a scourge and erodes public faith in the integrity of government.  Watching the protests from afar, at a distance of so many years, I was reminded of what I’d felt as a young foreign correspondent: awe and respect for the courage, tenacity and passion of the South Korean public.  This is not a tame society, for all the comforts its public has won in the years since. This may be the land of Psy and Gangnam style, a country so wired that some of its children are sent to boot camps to wean them from internet addiction.  But in a capital I’m told I would find unrecognizably sleek and affluent, in a system still encumbered by remnants of the security state, I recognize something I came to know well years ago: Politicians buck the popular will at their peril.  A version of this article appears in print on December 11, 2016, on page A12 of the New York edition with the headline: Protests Carry Echoes Of South Korea’s Past. Order Reprints| Today's Paper|Subscribe
In 1987, the demonstrations were far more violent than those of today. But the passions of those demanding change still burn bright.