On Friday, August 13, US Special Envoy for Afghanistan Zalmay Khalilzad issued a last-minute plea on Twitter, calling for “an immediate end to attacks” and “a political settlement" to the spiralling crisis that would soon see the Taliban return to power.
Two days later, the Taliban were flying their flag across Kabul. President Ashraf Ghani had fled the country, and chaos engulfed the capital as thousands of Afghans flocked to the airport in a frantic bid to flee.
Years of gruelling negotiations, the fruits of months of international hopscotch to meet world leaders and any tangible rewards from a painstaking push to make a deal with the Taliban had all melted away, almost overnight.
Once a prolific social media user - with 1,112 tweets since creating his account in November 2018 - Mr Khalilzad has remained conspicuously quiet in the days since the Taliban takeover, creating an information vacuum that critics have piled into.
Put simply, experts and sources who have worked with Mr Khalilzad say the Taliban outmanoeuvred him.
At the heart of the criticism is the February 2020 deal Mr Khalilzad forged with the Taliban.
Not only did it exclude Mr Ghani's US-backed former government, it granted broad concessions to the Taliban including a requirement for Mr Ghani to release 5,000 militant prisoners in return for only 1,000 pro-Ghani captives.
In return, the Taliban promised not to attack US forces as they left Afghanistan and to open peace talks in Doha with members of the Kabul government.
But it was clear there was a disconnect between what Mr Khalilzad was hearing from the Taliban during months of talks in Doha and what was happening on the ground.
Even as the hardliners stressed the importance of a diplomatic end to the conflict, their foot-soldiers were unleashing brutal assaults on demoralised Afghan forces.
And the Taliban never agreed to break ties with Al Qaeda, instead only promising to stop the group "from using the soil of Afghanistan to threaten the security of the United States and its allies".
Colin Clarke, director of policy and research at the Soufan Centre and an expert in counter-terrorism, said Mr Khalilzad’s recent quiet was predictable.
“I’m not surprised by his silence, given how spectacularly everything has unravelled,” Mr Clarke told The National.
Mr Clark pointed to other issues in the deal including an overemphasis on the US withdrawal in return for only vague Taliban commitments.
“It signalled a death knell for the prospects of any serious and sustained political settlement,” Mr Clarke said.
He added that a power-sharing deal with the Taliban in Kabul, something Mr Khalilzad had touted, was never likely.
Mr Khalilzad was not immediately available for comment for this story.
It is not the first time the 70-year-old Mr Khalilzad, who was born in Mazar-i-Sharif in Afghanistan, has been willing to give the Taliban the benefit of the doubt.
Writing in The Washington Post in 1996, he claimed “the Taliban do not practice the anti-US style of fundamentalism practised by Iran”.
Five years later, under the protection of the Taliban, Al Qaeda planned and carried out the September 11 attacks.
Ryan Crocker, ambassador to Afghanistan under Barack Obama, told The National last week that the agreement amounted to nothing less than a “surrender” deal.
During negotiations in Doha between Mr Khalilzad and Taliban co-founder Abdul Ghani Baradar, US relations soured with Mr Ghani and many in Kabul grew resentful of the envoy's apparent chummy relations with the Taliban.
The now-exiled president and Mr Khalilzad met on an exchange programme at a US high school and they later both studied at the American University of Beirut.
But their relationship was always fraught and they viewed each other suspiciously upon entering politics.
Mr Ghani and his associates have questioned Mr Khalilzad's motives in Afghanistan, going so far as to accuse him of having his own political ambitions.
“The perception in Afghanistan [was that] perhaps all of this talk is to create a caretaker government, of which he will then become the viceroy,” Mr Ghani's then-national security adviser, Hamdullah Mohib, said during a visit to the US in 2019.
Mr Khalilzad was appointed special envoy to Afghanistan by former president Donald Trump, but maintained the role under Mr Biden, signalling the US had little interest in altering course from the 2020 deal.
One former US embassy official in Kabul who closely followed Mr Khalilzad's work described him as someone pushing his own agenda.
Mr Khalilzad "stayed on the job after the US-Taliban agreement, even though he knew full well that Ghani and his team did not trust him,” the former US official told The National.
Speaking on condition of anonymity due to the sensitivity of the situation, the source said Mr Khalilzad “was exactly the wrong person to facilitate the intra-Afghan talks” because of his toxic relationship with Kabul.
“His ambition to get a bigger job in a second Trump administration, and then his desperate scramble to clean the Trump stink off after Biden won, prevailed," the source said.
Those that defend Mr Khalilzad point to his long career of service and his delivery of a deal that two successive administrations wanted in place.
The Taliban contacted Mr Khalilzad in 2018, helping to bolster his credentials for special envoy, the source said, describing Mr Khalilzad as “a master of making himself seem ‘indispensable’".
“His modus operandi has long been to keep information asymmetrical so that he is one step ahead of his colleagues [by design] and the gatekeeper of access to key contacts.”
For the Biden administration, keeping Mr Khalilzad in the position he had in the Trump administration appeared to be a calculated risk.
One State Department official said Mr Khalilzad's intimate knowledge of the deal, having close access to the Taliban and Mr Biden’s strong desire to leave Afghanistan helped keep him in the position.
But with the Taliban taking full control of Afghanistan and the US quickly running out of time to complete its withdrawal from the country by August 31, frustrations are growing at both the White House and the Pentagon about Mr Khalilzad’s role.
CNN reported that the Biden administration quietly sent Salman Ahmed, the State Department director for policy planning, to join Mr Khalilzad in Doha.
In the US Congress, Mr Khalilzad has been absent from Afghanistan briefings.
Michael Waltz, a Republican congressman and an Afghanistan war veteran, even called for Mr Khalilzad’s resignation.
“Ambassador Khalizad has provided you with poor counsel and his diplomatic strategy has failed spectacularly,” Mr Waltz said in a letter to Mr Biden.
He added that the envoy has convinced multiple administrations that the Taliban is interested in governing and peace while “it is only interested in brutality and power".
"In light of this catastrophe, Ambassador Khalilzad should resign immediately or be relieved from his position.”