Not quite a month ago, Yau Wai-ching glanced down at her phone to read the words she had prepared for the moment, a pledge to "be faithful and bear true allegiance to the Hong Kong nation."
It was a deliberate provocation, a mangling of the oath of office for new legislators in the city, who must swear fealty to "the Hong Kong Special Administrative Region of the People's Republic of China." Ms. Yau refused, unfurling instead a flag emblazoned with the words "Hong Kong is not China." She was determined to do things differently, as one of several convention-busting young candidates who have raucously challenged mainland China's increasingly tight grip on their city.
But the bomb she tossed with fellow elected legislator Baggio Leung, who also misspoke his oath, has now been thrown back by Beijing, which has moved to bar the two from office.
In an extraordinary reach into the electoral politics of Hong Kong, the standing committee of China's National People's Congress unanimously passed a Monday morning edict under the guise of an "interpretation" of Hong Kong's constitution-like Basic Law. It disqualifies from office anyone who does not make a sincere or accurate oath, and also pledges to hold liable legislators found in breach of their own oaths, a threat that raised worry targets have now been placed on others in Hong Kong willing to challenge Beijing's primacy.
For China, a failure to quickly fight back against such defiance "would seriously damage state sovereignty, security and the benefits of development, and would endanger Hong Kong's prosperity and stability," said Li Fei, who chairs the country's Basic Law Committee.
"Activities that advocate a splitting of the nation or 'Hong Kong independence' shall in no way be allowed," a spokesperson with the Hong Kong and Macao Affairs Office of the State Council said in remarks reported by state-run news agency Xinhua.
Hong Kong was handed over to Chinese rule in 1997 with a promise that it could retain a high degree of autonomy.
Not quite 20 years later, "we're beginning to see what we feared most: living under communist rule," said Jason Y. Ng, a political commentator who wrote the book Umbrellas in Bloom, which documented street protests in 2014.
Unless one side takes steps to lower the temperature, "we are escalating toward an all-out rebellion and a complete ungovernability of Hong Kong," he said.
Instability has already jolted the city in recent years, with protesters demanding China stay out of school textbooks and back out of local electoral politics. The 2014 "Umbrella Movement" occupied the heart of the city for 79 days and unleashed a political movement that voted Ms. Yau and five other outspoken young faces into the city's Legislative Council this fall.
Now, two of those legislators may be out – and others worry they may follow.
If Beijing continues to pressure, "I will probably be the next one or two legislators to be disqualified," said Eddie Chu, one of the young lawmakers who in reciting his own oath called for "democracy and self-determination – autocracy will die." Beijing now appears to be treating calls for "self-determination" and "independence" as equally serious offences, and Mr. Chu fears his words will be used against him.
They "may charge me with the offence of not following the oath," he said.
On Monday, Lau Siu-kai, the vice-chairman of the Chinese Association of Hong Kong and Macau Studies, seemed to confirm that possibility after a meeting with Beijing's top representative in Hong Kong.
There "may be other people who will raise judicial reviews to the courts to challenge these seats in future," Prof. Lau told the South China Morning Post.
China is merely acting to ensure Hong Kong has a "correct understanding" of what China will allow inside a "regional unit," said Zhang Dinghuai, deputy director of the Center for Basic Laws of Hong Kong and Macau Special Administrative Regions at Shenzhen University.
"It's to alert Hong Kong society. This is the political bottom line and it cannot be touched," he said. "It's like in a family. It's okay for family members have different opinions, but if the son says he intends to kill the father, that's not a normal freedom-of-speech issue, is it?"
Yet Beijing's interpretation will itself need to be applied by courts in Hong Kong, which are at the same time dealing with thorny issues regarding the eligibility of other independence-minded candidates to run for office.
"It's not the nail in the coffin that I think they would want to see. I think this is just the start of something else," said Simon Young, a law professor at the University of Hong Kong.
"We may have to go back for a second and even a third interpretation to deal with those cases," he said. "It's extremely chaotic."
Fresh street violence broke out Sunday night, when Hong Kong police used pepper spray, riot shields and batons to disperse a crowd of protesters, some of whom wore umbrellas and Guy Fawkes masks in anger over Chinese interference.
Critics say Beijing is increasingly willing to rule Hong Kong by dictate rather than let the city govern itself.
In Beijing, however, Hong Kong's brash new legislators are seen as a rabble-rousing, slanderous affront.
"Mr. Leung and Ms. Yau publicly disgraced this country and advocated Hong Kong does not belong to China," the Communist Party-run Global Times said in an editorial Monday. "The fallacies they created must be cleaned up."
– with reporting by Yu Mei