SAN FRANCISCO • Ms Sheryl Sandberg was seething. Inside Facebook's Menlo Park, California, headquarters, top executives gathered in the glass-walled conference room of its founder, Mr Mark Zuckerberg.

It was September last year, over a year after Facebook engineers discovered suspicious Russia-linked activity on its site, an early warning of the Kremlin campaign to disrupt the 2016 US presidential election. Congressional and federal investigators were closing in on evidence that would implicate the company.

But it was not the looming disaster at Facebook that angered Ms Sandberg. It was the social network's security chief, Mr Alex Stamos, who had informed company board members the day before that Facebook had yet to contain the Russian infestation.

Mr Stamos' briefing had prompted a humiliating boardroom interrogation of Ms Sandberg, Facebook's chief operating officer, and her billionaire boss.

"You threw us under the bus!" she yelled at Mr Stamos, according to people who were present.

The clash that day would set off a reckoning - for Mr Zuckerberg, for Ms Sandberg and for the business they had built together.

In just over a decade, Facebook has connected more than 2.2 billion people, a global nation unto itself that reshaped political campaigns, the advertising business and daily life around the world.

But as evidence accumulated that Facebook's power could also be exploited to disrupt elections, broadcast viral propaganda and inspire deadly campaigns of hate around the globe, Mr Zuckerberg and Ms Sandberg stumbled.

Bent on growth, the pair ignored warning signs and then sought to conceal them from public view.

When Facebook users learnt in spring that the company had compromised their privacy in its rush to expand, allowing access to the personal information of tens of millions of people to a political data firm linked to President Donald Trump, Facebook sought to deflect blame and mask the extent of the problem.

And when that failed - as the company's stock price plummeted and sparked a consumer backlash - Facebook went on the attack.

While Mr Zuckerberg conducted a public apology tour in the past year, Ms Sandberg has overseen an aggressive lobbying campaign to combat Facebook's critics, shift public anger towards rival companies and ward off damaging regulation.

Facebook employed a Republican opposition-research firm to discredit activist protesters, in part by linking them to liberal financier George Soros. It also tapped its business relationships, persuading a Jewish civil rights group to cast some criticism of the company as anti-Semitic.

In Washington, allies of Facebook, including Senator Chuck Schumer, the Democratic Senate leader, intervened on its behalf. And Ms Sandberg wooed or cajoled hostile lawmakers, while trying to dispel Facebook's reputation as a bastion of Bay Area liberalism.

This account of how Mr Zuckerberg and Ms Sandberg navigated Facebook's cascading crises, much of which has not been previously reported, is based on interviews with more than 50 people.

They include current and former Facebook executives and other employees, lawmakers and government officials, lobbyists and congressional staff members.

Most spoke on the condition of anonymity because they had signed confidentiality agreements, were not authorised to speak to reporters or feared retaliation.

Facebook declined to make Mr Zuckerberg and Ms Sandberg available for comment. In a statement, a spokesman acknowledged that Facebook had been slow to address its challenges, but had since made progress fixing the platform.

"This has been a tough time at Facebook, and our entire management team has been focused on tackling the issues we face," the statement said.

"While these are hard problems, we are working hard to ensure that people find our products useful and that we protect our community from bad actors."

Even so, trust in the social network has sunk, while its pell-mell growth has slowed. Regulators and law enforcement officials in the US and Europe are investigating Facebook's conduct with Cambridge Analytica, a political data firm that worked with Mr Trump's 2016 campaign, opening up the company to fines and other liability.

Both the Trump administration and lawmakers have begun crafting proposals for a national privacy law, setting up a years-long struggle over the future of Facebook's data-hungry business model.

"We failed to look and try to imagine what was hiding behind corners," Mr Elliot Schrage, former vice-president for global communications, marketing and public policy at Facebook, said in an interview.

Mr Zuckerberg, 34, and Ms Sandberg, 49, remain at the company's helm, while Mr Stamos and other high-profile executives have left after disputes over Facebook's priorities.

'Don't poke the bear'

Three years ago, Mr Zuckerberg, who founded Facebook in 2004 while attending Harvard, was celebrated for the company's extraordinary success.

Ms Sandberg, a former Clinton administration official and Google veteran, had become a feminist icon with the publication of her empowerment manifesto, Lean In, in 2013.

Like other technology executives, Mr Zuckerberg and Ms Sandberg cast their company as a force for social good.

Facebook's lofty aims were emblazoned even on securities filings: "Our mission is to make the world more open and connected."

But as Facebook grew, so did the hate speech, bullying and other toxic content on the platform.

When researchers and activists in Myanmar, India, Germany and elsewhere warned that Facebook had become an instrument of government propaganda and ethnic cleansing, the company largely ignored them.

Facebook had positioned itself as a platform, not a publisher. Taking responsibility for what users posted, or acting to censor it, was expensive and complicated. Many Facebook executives worried that any such efforts would backfire.

Then Mr Trump ran for president. He described Muslim immigrants and refugees as a danger to America, and in December 2015, posted a statement on Facebook calling for a "total and complete shutdown" on Muslims entering the US. His call to arms was shared more than 15,000 times on Facebook, an illustration of the site's power to spread racist sentiment.

Mr Zuckerberg, who had helped found a non-profit dedicated to immigration reform, was appalled, said employees who spoke to him or were familiar with the conversation. He asked Ms Sandberg and other executives if Mr Trump had violated Facebook's terms of service.

In 2010, Ms Sandberg, a Democrat, had recruited a friend and fellow Clinton alumnus, Mr Marne Levine, as Facebook's chief Washington representative.

A year later, after Republicans seized control of the House, Ms Sandberg installed another friend, a well-connected Republican: Mr Joel Kaplan, who had attended Harvard with Ms Sandberg.

Some at Facebook viewed Mr Trump's 2015 attack on Muslims as an opportunity to finally take a stand against the hate speech coursing through its platform.

But Ms Sandberg, who was edging back to work after the death of her husband several months earlier, delegated the matter to Mr Schrage and Ms Monika Bickert, a former prosecutor whom Ms Sandberg had recruited as the company's head of global policy.

Ms Sandberg also turned to the Washington office - particularly to Mr Kaplan, said people who participated in or were briefed on the discussions.

Mr Kaplan argued that Mr Trump was an important public figure and that shutting down his account or removing the statement could be seen as obstructing free speech, said three employees who knew of the discussions.

He also said it could stoke a conservative backlash.

"Don't poke the bear," Mr Kaplan warned.

Mr Schrage concluded that Mr Trump's language had not violated Facebook's rules and that the candidate's views had public value.

In the end, Mr Trump's statement and account remained on the site, and he won election the next autumn.

But inside Facebook, new troubles were brewing.

Minimising Russia's role

In the final months of Mr Trump's presidential campaign, Russian agents escalated a year-long effort to hack and harass his Democratic opponents, culminating in the release of thousands of e-mails stolen from prominent Democrats and party officials.

Facebook had said nothing publicly about any problems on its own platform. But in the spring of 2016, a company expert on Russian cyber warfare spotted something worrisome. He reached out to his boss, Mr Stamos.

Mr Stamos' team discovered that Russian hackers appeared to be probing Facebook accounts for people connected to the presidential campaigns, said two employees.

Months later, as Mr Trump battled Mrs Hillary Clinton in the election, the team also found Facebook accounts linked to Russian hackers who were messaging journalists to share information from the stolen e-mails.

Mr Stamos, 39, told Mr Colin Stretch, Facebook's general counsel, about the findings, said two people involved in the conversations. Mr Stamos, acting on his own, then directed a team to scrutinise the extent of Russian activity on Facebook.

In December 2016, after Mr Zuckerberg publicly scoffed at the idea that fake news on Facebook had helped elect Mr Trump, Mr Stamos - alarmed that the company's chief executive seemed unaware of his team's findings - met Mr Zuckerberg, Ms Sandberg and other top Facebook leaders.

Ms Sandberg was angry. Looking into the Russian activity without approval, she said, had left the company exposed legally. Still, Ms Sandberg and Mr Zuckerberg decided to expand on Mr Stamos' work, creating a group called Project P, for "propaganda", to study false news on the site, according to people involved in the discussions.

By January last year, the group knew that Mr Stamos' original team had only scratched the surface of Russian activity on Facebook, and pressed to issue a public paper about their findings. But Mr Kaplan and other Facebook executives objected. Washington was already reeling from an official finding by US intelligence agencies that Mr Vladimir Putin, the Russian President, had personally ordered an influence campaign aimed at helping elect Mr Trump.

If Facebook implicated Russia further, Mr Kaplan said, Republicans would accuse the company of siding with Democrats. And if Facebook pulled down the Russians' fake pages, regular Facebook users might also react with outrage at having been deceived.

Ms Sandberg sided with Mr Kaplan, recalled four people involved. Mr Zuckerberg - who spent much of last year on a national "listening tour", feeding cows in Wisconsin and eating dinner with Somali refugees in Minnesota - did not participate in the conversations about the public paper. When it was published that April, the word "Russia" never appeared.

Ms Sandberg's subordinates took a similar approach in Washington, where the Senate had begun pursuing its own investigation, led by Mr Richard Burr, a North Carolina Republican, and Mr Mark Warner, a Virginia Democrat.

Throughout the spring and summer of last year, Facebook officials repeatedly played down Senate investigators' concerns about the company, while publicly claiming there had been no Russian effort of any significance on Facebook. But employees were tracing more ads, pages and groups back to Russia.

By August last year, Facebook executives concluded that the situation had become what one called a "five-alarm fire", said a person familiar with the discussions. Mr Zuckerberg and Ms Sandberg agreed to go public with some findings, and laid plans to release a blog post on Sept 6 last year, the day of the company's quarterly board meeting.

After Mr Stamos and his team drafted the post, however, Ms Sandberg and her deputies insisted it be less specific. She and Mr Zuckerberg also asked Mr Stamos and Mr Stretch to brief the board's audit committee, chaired by Mr Erskine Bowles, the patrician investor and White House veteran.

When the full board gathered later that day in a room at the company's headquarters, Mr Bowles pelted questions at Facebook's founder and second-in-command.

Ms Sandberg, visibly unsettled, apologised. Mr Zuckerberg, stone-faced, whirred through technical fixes, said three people who attended or were briefed on the proceedings.

Later that day, the company's abbreviated blog post went up. It said little about fake accounts or the organic posts created by Russian trolls that had gone viral on Facebook, disclosing only that Russian agents had spent roughly US$100,000 (S$138,000) - a relatively tiny sum - on approximately 3,000 ads.

Just one day after the company's carefully sculpted admission, The Times published an investigation of further Russian activity on Facebook, showing how Russian intelligence had used fake accounts to promote e-mails stolen from the Democratic Party and prominent Washington figures.

A political playbook

The revelations infuriated Democrats who now blamed Mr Trump's win partly on Facebook's tolerance for fraud and disinformation. Republicans, already concerned that the platform was censoring conservative views, accused Facebook of fuelling what they said were meritless conspiracy charges against Mr Trump and Russia.

After stalling for weeks, Facebook eventually agreed to hand over the Russian posts to Congress. Twice in October last year, Facebook was forced to revise its public statements, finally acknowledging that close to 126 million people had seen the Russian posts.

The same month, Mr Warner and Senator Amy Klobuchar, a Minnesota Democrat, introduced legislation to compel Facebook and other Internet firms to disclose who bought political ads on their sites.

Facebook girded for battle. Days after the Bill was unveiled, Facebook hired Mr Warner's former chief of staff, Mr Luke Albee, to lobby on it. In October last year, Facebook also expanded its work with a Washington-based consultant, Definers Public Affairs, which had originally been hired to monitor press coverage of the company.

Founded by veterans of Republican presidential politics, Definers specialised in applying political campaign tactics to corporate public relations. It had established a Silicon Valley outpost earlier that year, led by Mr Tim Miller, a former spokesman for Mr Jeb Bush who preached the virtues of campaign-style opposition research.

For tech firms, he argued in one interview, a goal should be to "have positive content pushed out about your company and negative content that's being pushed out about your competitor".

Facebook quickly adopted that strategy. In November last year, the social network came out in favour of a Bill called the Stop Enabling Sex Traffickers Act, which made Internet companies responsible for sex trafficking ads on their sites.

Google and others had fought the Bill for months, worrying it would set a cumbersome precedent.

Opposition research

In March, The Times and The Observer/Guardian prepared to publish a joint investigation into how Facebook user data had been appropriated by Cambridge Analytica to profile American voters.

A few days before publication, The Times presented Facebook with evidence that copies of improperly acquired Facebook data still existed, despite earlier promises by Cambridge executives and others to delete it.

Mr Zuckerberg and Ms Sandberg decided to pre-empt the stories, saying in a statement published late on a Friday night that Facebook had suspended Cambridge Analytica from its platform. The executives figured that getting ahead of the news would soften its blow, according to people in the discussions.

They were wrong. The story drew worldwide outrage, prompting lawsuits and official investigations in Washington, London and Brussels.

In Silicon Valley, other tech firms began exploiting the outcry to burnish their own brands.

"We're not going to traffic in your personal life," Mr Tim Cook, Apple's chief executive, said in an MSNBC interview. "Privacy to us is a human right. It's a civil liberty."

Then Facebook went on the offensive and expanded its work with Definers. On a conservative news site called the NTK Network, dozens of articles blasted Google and Apple for unsavoury business practices.

One story called Mr Cook hypocritical for chiding Facebook over privacy, noting that Apple also collects reams of data from users. The rash of news coverage was no accident: NTK is an affiliate of Definers.

In public, Facebook was more conciliatory. Mr Zuckerberg agreed to testify on Capitol Hill. Days before his appearance in Congress in April, Facebook announced that it was endorsing Ms Klobuchar's Honest Ads Bill and would pre-emptively begin disclosing political ad buyers. It also informed users whose data had been improperly harvested by Cambridge Analytica.

Yesterday, the Times reported that Facebook has ended its relationship with Definers, according to a person familiar with the decision. In a statement, Facebook said it had not hidden its ties to Definers and disputed that it had asked the firm to spread false information.

Personal appeals

At one company gathering, said two people who knew of the event, friends told Ms Sandberg that if Facebook did not address the scandals effectively, its role in spreading hate and fear would define her legacy, too.

So Ms Sandberg began taking a more personal role in the company's Washington campaign, drawing on all the polish that Mr Zuckerberg sometimes lacked.

She not only relied on her old Democratic ties, but also sought to assuage sceptical Republicans, who grumbled that Facebook was more sensitive to the political opinions of its workforce than to those of powerful committee leaders.

Trailing an entourage of as many as 10 people on trips to the capital, Ms Sandberg made a point of sending personal thank-you notes to lawmakers and others she met.

The war room

One morning in late summer, workers layered opaque contact paper onto the windows of a conference room in Facebook's Washington office. Not long after, a security guard was posted outside the door.

It was an unusual sight: Facebook prided itself on open office plans and transparent, glass-walled conference rooms.

But Ms Sandberg was set to testify before the Senate Intelligence Committee - a pivotal encounter for her embattled company - and her aides were taking no chances.

Inside the room, they laboured to prepare her for the hearing. They had assembled a binder-size briefing book, covering virtually every issue she might be questioned about, and had hired a former White House lawyer who specialised in training corporate executives.

Facebook lobbyists had already worked the Intelligence Committee hard, asking that lawmakers refrain from questioning Ms Sandberg about privacy issues, Cambridge Analytica and censorship.

The argument was persuasive with Mr Burr, who was determined to avoid a circus-like atmosphere. A day before the hearing, he issued a stern warning to all committee members to stick to the topic of election interference.

Facebook had lobbied for the hearing to include a Google emissary of similar rank to Ms Sandberg. The company won a partial victory when Mr Burr announced that Mr Larry Page, a Google co-founder, had been invited, along with Mr Jack Dorsey, Twitter's chief executive.

Mr Dorsey showed up. Mr Page did not.

As the hearing unfolded, senators excoriated Google for its absence, earning a wave of negative news coverage for Facebook's rival.

Ms Sandberg spread neatly handwritten notes on the table before her: the names of each senator on the committee, their pet questions and concerns, a reminder to say "thank you".

In large letters were her stage directions: "Slow, Pause, Determined."

NYTIMES