Facebook has effectively given up on bringing its services to China, its chief executive Mark Zuckerberg has confirmed, signalling a decisive end to the social media giant's ambition to enter that market.
In a speech at Georgetown University in Washington DC, he said that Facebook had tried and failed to reach agreement with the Chinese government over internet censorship and government access to users' personal data.
The 35-year-old founder used his address to position Facebook as a guardian of free expression, warning that critics of Western tech companies should be wary of allowing them to lose control of the internet to less liberal Chinese services.
He also criticised the "dangerous" trend of opposition to free speech inside Western democracies, saying that too many people had come to believe that their "political objectives" were so important as to justify the suppression of their opponents' opinions.
"China is building its own internet focused on very different values, and now it's exporting their vision of the internet to other countries," Mr Zuckerberg told students at the private university, known as a hothouse for future politicians, judges and diplomats.
"Until recently, the internet in almost every country outside of China has been defined by American platforms with strong free expression values. But there's no guarantee that these values will win out...
"I wanted our services in China because I believe in connecting the whole world, and I thought maybe we could help create a more open society. And this is one that I worked hard on for a long time.
"But we could never come to agreement on what it would take for us to operate there, and they never let us in. Now we have more freedom to speak out and stand up for the values that we believe in, and fight for free expression around the world."
That statement was a reversal of the stance that Facebook held as recently as November 2018. The social network was kicked out of China in 2009, along with Twitter, after its services were blamed for facilitating separatist riots in the autonomous region of Xinjiang which killed 197 people and led to more than 1,500 arrests.
Yet Mr Zuckerberg did not give up, paying multiple visits to Chinese leaders and tech executives, delivering a speech in awkward Mandarin at Beijing's Tsinghua University in 2015 and authorising internal research into software that would have allowed a Chinese partner company to monitor and censor certain topics on Facebook in real time.
Last November, as Google came under fire for secretly building a censored search engine known as"Project Dragonfly", Facebook told the US Senate that "no decisions have been made" about the conditions under which it might return to China, saying only that any potential risks to free expression and privacy would be given "careful consideration".
In March, however, in a long blog post describing Facebook's strategic shift towards private messaging, Mr Zuckerberg said that the company would not store "sensitive data" in countries with "weak records on human rights" in order to avoid hurting dissidents or putting Facebook employees in danger. That would rule out China, where keeping personal information within its borders is a legal requirement.
In his speech at Georgetown, Mr Zuckerberg also defended Facebook's policy of allowing politicians to broadcast misleading adverts, saying that tech companies should not be the judge of what is true or not and that restricting political adverts too heavily would only favour incumbents who already possess institutional power.
That was part of a wider argument that Facebook, far from centralising power over the internet and free speech by putting much of it under the control of one company, has enhanced the power of individuals and diminished that of traditional gatekeepers such as the media.
"Some hold the view that since the stakes are so high that they can no longer trust their fellow citizens with the power to communicate and decide what to believe for themselves," Mr Zuckerberg said. "I personally believe that this is more dangerous for democracy over the longer term than any political speech."
Mr Zuckerberg referenced Martin Luther King Jr in his speech and his being jailed for peacefully protesting, saying: "Pulling back on free expression wasn't the answer and, in fact, it often ended up hurting the minority views we seek to protect".
The comments drew criticism from Bernice King, the daughter Martin Luther King Jr, who wrote on Twitter that she would "like to help Facebook better understand the challenges #MLK faced from disinformation campaigns launched by politicians".
She said such "campaigns created an atmosphere for his assassination".
Facebook has been frequently criticised for how it polices its services, with American conservatives accusing it of systematic Left-wing bias and Left-wingers saying that it treats hate speech with kid gloves.
Mr Zuckerberg even suggested that if Facebook had existed in 2003, when he was a student at Harvard University, then the Iraq War might not have happened because more people would have been able to voice their opposition.
"Most of us felt powerless to stop it," he said. "I remember feeling that if more people had a voice to share their experiences, maybe things would have gone differently."