Zalmay Khalilzad, the US's envoy in the Taliban talks, has worked with Taliban envoys over months in Qatar to take steps toward the withdrawal of US troops from Afghanistan. According to TIME, US Secretary of Defense Mark Esper was supposed to discuss the deal with US President Donald Trump on Tuesday. If the deal is signed, 5,400 US troops would leave Afghanistan within 135 days, Business Insider reports.

But TIME reports that the deal doesn't guarantee the survival of the US-supported Afghan government, which the Taliban considers a puppet government and which the US expects the Taliban to negotiate with in Oslo after a deal is completed.

Even if an Afghan government should survive, its relationship to the US will be permanently damaged after the negotiation, TIME reports. While Afghan president Ashraf Ghani has publicly agreed to the negotiations and will send a delegation to Oslo to deal with the Taliban, the US envoy Khalilzad refuses to show him a draft of the agreement.

"It is all based on hope. There is no trust. There is no history of trust. There is no evidence of honesty and sincerity from the Taliban," an Afghan official with knowledge of the negotiation told TIME's Kimberly Dozier. According to the official, the Taliban "think they have fooled the U.S. while the U.S. believes that should the Taliban cheat, they will pay a hefty price."

TIME reports that the deal also doesn't guarantee that US counterterrorism forces will be able to stay in Afghanistan to fight al-Qaeda — the original mission of the US's invasion of Afghanistan — or that violence in Afghanistan will stop once a deal is reached.

While those reasons alone may have deterred Pompeo from signing the deal, TIME also reports that the Taliban asked the US to sign a deal with the Islamic Emirate of Afghanistan, the name the Taliban gave itself when it came to power in Afghanistan in 1996. Pompeo's refusal to sign the deal may also be a refusal to recognize the Taliban as the government of Afghanistan.

The Afghanistan war has always been a Sisyphean project for the US, but the negotiations with the Taliban present yet another situation in which the US was forced to choose the worst of several bad options.