HONG KONG -- It was a watershed moment for Hong Kong's Legislative Council.
In an unprecedented move, Beijing on Wednesday decided to give sweeping powers to the Hong Kong government to remove any lawmakers deemed insufficiently patriotic.
Four opposition members were ousted from the legislature within minutes after the announcement as the chamber speaker suspended proceedings. Hours later, 15 other opposition lawmakers fulfilled a pledge made the previous day to jointly resign in case of any ejections, leaving the Legislative Council with no opposition for the remaining 10 months of its extended term -- or perhaps forever.
Here are five things you need to know about the mass resignation of Hong Kong opposition lawmakers.
What did Beijing announce?
The National People's Congress Standing Committee, China's top decision-making body, passed a resolution on Wednesday that gave Hong Kong authorities the power to oust any lawmakers on national security grounds without going through local courts.
"We need to have a political body composed of patriots," said Chief Executive Carrie Lam at a subsequent briefing, echoing a view expressed by mainland authorities.
The resolution stipulated that lawmakers would be disqualified if they are ruled to have promoted or supported Hong Kong independence, refused to acknowledge China's sovereignty over Hong Kong, sought foreign forces' interference in Hong Kong affairs, or committed other acts jeopardizing national security.
As Kenneth Leung, one of the disqualified lawmakers, put it: "The government can now remove any faces it dislikes from the chamber... There will be no future for this legislature."
Why did the whole pro-democracy bloc resign?
Pro-democracy lawmakers have always been in the minority in Hong Kong's semi-democratic legislature, due to the design of the city's electoral system and the allotment of nearly half the seats to industry groups.
In recent years, Beijing has tightened its grip over the council. Opposition lawmakers have been disqualified, controversial bills have been forced through and the election that had been scheduled for Sept. 6 was postponed after the nominating period, ostensibly over concerns about a COVID-19 flare-up.
The delay -- which quashed the opposition camp's ambition of winning its first majority in the legislature, following a landslide victory in neighborhood council elections last year -- triggered calls from the bloc's supporters for a boycott of the legislature.
Although three pro-democracy legislators left at the previously scheduled end of their terms in September, the others stayed on after a survey of supporters. Beijing's resolution on Wednesday was the last straw, however, as it seemed to leave little room for opposition in the future.
"There's no point in doing this job if you can't do it properly," said Dennis Kwok, one of the ousted lawmakers.
Can Beijing's decision be legally challenged?
The legal basis of such a resolution is unclear, according to Johannes Chan, a law scholar at the University of Hong Kong.
"We have seen the NPCSC is above the law. They can just pass any decision or stop any decision without any regard for the procedures of the Basic Law," Chan told public broadcaster RTHK, referring to the city's constitution. "It can be interpreted arbitrarily."
He continued, "I think inevitably people's confidence in the rule of law will be undermined and increasingly, it seems the Basic Law is getting more and more irrelevant in Hong Kong."
While the ousted lawmakers said they are pondering whether to challenge their removal in court, it is unlikely that the judiciary, which has come under increasing pressure from Beijing authorities, can reverse the central government's ruling.
Maria Tam, vice chairwoman of the Basic Law Committee, told RTHK that opposition lawmakers are almost certain to lose if they file election petitions or a judicial challenge.
"NPC Standing Committee decisions are not challengeable, as it is the top lawmaking body in China," she said. "Any judicial review would almost certainly fail because the authorities would cite the NPCSC."
How is the international community reacting?
Beijing's decision came a day after the U.S. government imposed a new round of sanctions on Hong Kong officials found to be responsible for human rights violations in the former British colony, adding to previous moves to revoke special trade and investment privileges for the financial hub following China's imposition of a new national security law covering the territory last June.
Following the disqualifications of the lawmakers, Washington warned of further sanctions against China, which it said has "flagrantly violated" the high degree of autonomy promised to Hong Kong during the 1997 handover.
"Beijing's recent actions disqualifying pro-democracy legislators from Hong Kong's Legislative Council leave no doubt that the Chinese Communist Party has flagrantly violated its international commitments," said Robert O'Brien, U.S. national security adviser. "We will continue to identify and sanction those responsible for extinguishing Hong Kong's freedom."
Other Western governments including the U.K. and Australia have also condemned China's move.
"China's decision... represents a further assault on Hong Kong's high degree of autonomy and freedoms under the U.K.-China Joint Declaration," said British Foreign Minister Dominic Raab. "This campaign to harass, stifle and disqualify democratic opposition tarnishes China's international reputation and undermines Hong Kong's long-term stability."
What's next for Hong Kong?
The mass resignation of opposition lawmakers leaves two independent members out of 43 remaining in the 70-seat chamber.
As the government previously ruled out by-elections to fill existing vacancies, citing the pandemic, the legislature looks likely to operate without opposition going forward, similar to the rubber-stamp parliament in mainland China.
Lam said she was "excited" that government bills might be passed more quickly in the council without opposition lawmakers, as they have been using filibustering tactics to delay contentious government legislation, including a controversial plan to reclaim a new island from the sea and proposals to allow Hong Kongers living in mainland China to vote absentee.
"The government will be able to pass all bills in a speedy manner before the public even notices," said Gary Tang, an assistant professor at Hang Seng University of Hong Kong.
While pro-democracy lawmakers who stepped down have all vowed to continue their resistance outside of the legislature, Tang said they need to carefully utilize their political influence to raise international attention about important issues, without running afoul of the vague national security law.
"They have a fine line to walk," Tang said.