Carrie Lam, the Chief Executive of Hong Kong, regularly appears at press conferences these days wearing a medical mask—not an unusual sight for a head of government during the global pandemic. It’s nevertheless ironic for a leader who had banned the wearing of masks in public only five months ago, in an effort to help the police win back control of the city’s streets from throngs of masked protesters.

The mask ban, based on a century-old colonial emergency ordinance, was largely upheld earlier this month in a controversial ruling by Hong Kong’s Court of Final Appeal. By then, the Covid-19 crisis had stopped the mass protests, accomplishing what Carrie Lam and her officers could not during much of 2019. As one Hong Kong politician quipped, “It’s a bit funny to talk about the anti-mask ban when everyone is wearing [masks].”

While Carrie Lam’s Hong Kong government is imposing stringent lockdown measures, ostensibly to contain the pandemic, Beijing is pushing the chief executive to contain the opposition in Hong Kong, in hopes of deterring another round of public protests this summer. Over the weekend of April 18-19, the Hong Kong police arrested fifteen high profile opposition leaders. Both the accused and the police escorts were seen wearing medical masks as they filed into police stations for formal charges associated with their involvement during last year’s protests.

Of greater concern to many, including those arrested, have been Beijing’s moves to undermine the Basic Law, the mini-constitution that gives the Hong Kong government the power to manage local affairs. Beijing’s newly appointed representative in Hong Kong, the head of the Hong Kong Liaison Office, recently called for the government to pass a long-shelved National Security law which had sparked massive protests when it was first introduced in 2003. Many viewed this, like the arrests, as further evidence of Beijing’s violation of the Basic Law.

The first Covid-19 cases appeared in Hong Kong in January, at a time when protests were still being mounted in impressive numbers. Carrie Lam announced emergency measures in response to the pandemic on January 25, the first day of the Chinese New Year, when family visits around the city are customary. The public accepted Lam’s call to stay indoors, although she was roundly criticized for not wearing a medical mask at the press conference. Many surmised she had not done so on orders from Beijing, whose leaders still wished to prevent alarm around the world.

About a week later, frustrated by the Hong Kong government’s slow response to the crisis, medical workers launched a strike to demand the distribution of medical masks free to the public—and the closing of Hong Kong’s borders with China. Chief Executive Lam quickly conceded. Civic and charitable organizations in Hong Kong also mobilized to distribute medical masks across the city and did so effectively. Public opinion polls generally credit non-governmental organizations rather than the government for Hong Kong’s impressive initial management of the coronavirus.

In late March, in response to concerns over the re-emergence of Covid-19 cases inside Hong Kong, Lam announced that she was outlawing public gatherings of more than four people for two weeks. This time she wore a mask. The restrictions were later extended for two more weeks, and it remains to be seen whether they will be renewed again in late April. Limiting public gatherings to no more than four people may be a legitimate public health measure, but when the same government is arresting political opponents, it’s clear that the pandemic is being used by Lam’s bosses in Beijing to deter would-be protestors as the anniversaries of crucial dates approach.

Medical or face masks, designed originally for keeping out various allergens, dust, and pollution particles, were put to universal use in Hong Kong well before 2019. During the SARS pandemic of 2003, when a coronavirus was believed to have originated in an outdoor animal market in the nearby city of Guangzhou, Hong Kong citizens quickly turned to masks as a preventive measure. After SARS, masks could be seen in regular use on streets, trains, and restaurants during flu seasons in Hong Kong.

But beginning on June 9, 2019, wearing a mask of any kind in Hong Kong became a sign of resistance against the Hong Kong government. Last year’s protests, which had begun in opposition to an extradition bill, turned into a persistent and broad-based revolt against Beijing’s ongoing erosion of Hong Kong’s autonomy. Protesters demanded the creation of more genuinely democratic political institutions for the city.

On June 12, 2019, Police fired teargas on protestors massing outside the Hong Kong’s legislature compound in quantities that far exceeded the amount used during the 79-day Umbrella movement in 2014—so named for protestors who used umbrellas to deflect pepper spray and tear gas. A few days later, on June 16, an estimated quarter of the city’s 7.4 million residents turned out on the streets—an unprecedented display of “people power,” far beyond anything achieved during the 2014 movement. From then on, ranks of demonstrators wearing masks, black clothing, and hardhats became iconic images of the Hong Kong protests.

Masks also figured in several episodes of counter-mobilization against the protestors last summer. Masked thugs wielding sticks and other weapons set upon passengers and journalists at the Yuen Long metro station in the infamous attack on July 21 (known to many as “721”). At rallies later in the summer and fall, it was common to find reports of “masked men” setting upon individual opposition politicians and activists, inflicting serious wounds in some cases. Police who undertook actions against the protestors also began wearing masks and covering their badge identification numbers.

In October 2019, Chief Executive Lam unilaterally outlawed masks, drawing upon a colonial-era provision still on the books granting emergency powers to enact provisions to maintain public safety—even when such provisions were in violation of civil liberties. While the move was clearly made under pressure from Beijing, the provision originated from the former British colonial governor, who asserted the emergency powers in 1922, in the face of a massive general strike in Hong Kong.

After Hong Kong’s lower court ruled the mask ban unconstitutional in November 2019, China’s legislature asserted that only it, and not Hong Kong courts, had the power to interpret the constitutionality of the mask ban—or indeed of any law passed in Hong Kong. Given the ongoing erosion of Hong Kong’s judicial independence, it was unsurprising that the city’s Court of Final Appeal largely upheld the mask ban in its recent decision. The ruling clarified that the government had the power to arrest anyone wearing a mask at an “unlawful assembly.”

History repeats itself. During the pandemics of the 19th and early 20th centuries, colonial governments routinely invoked emergency powers to impose measures that became a permanent part of the regime’s toolkit. Meanwhile, colonial trade and commerce often caused the spread of diseases in the first place. Any public health emergency offers those in power—colonial or otherwise—an opportunity to claim extraordinary, extraconstitutional powers. As we’re seeing today, pandemics give a fresh excuse to executives like Orbán in Hungary and Trump in the United States to declare broad executive powers they had coveted long before the pandemic.

In Hong Kong, the balance of power is dangerously unstable, despite Carrie Lam’s recent arrest of prominent political opponents. If by early summer, the Covid-19 cases in Hong Kong appear to be under control—a big if—then massive protest marches will likely resume on June 9 and June 16, the milestone dates marking the largest and most consequential of last year’s protests. There could also be the annual vigil on June 4 to commemorate those who died in China in the 1989 Tiananmen Square crackdown on student demonstrators. On July 1, another public holiday marks the anniversary of the 1997 transfer of Hong Kong from British to Chinese rule.

It will be extremely tempting for the CCP and the Hong Kong government to use the threat of coronavirus contagion to deny protest permits, and to use aggressive coercive techniques to prevent any “unlawful assemblies.” But the protesters have the support of an exceptionally large number of Hong Kong citizens. Once again masked protestors may violently clash in the city’s streets and public buildings—even if the police now try to hide their harsh public security actions under the mask of defending public health and defeating Covid-19.

Mark W. Frazier is Professor of Politics at The New School, where he also serves as Academic Director of the India China Institute.