In a report that essentially confirms what Secretary Mattis only insinuated in his letter of resignation, the Associated Press offered an account sourced from anonymous US and Turkish officials that appears to confirm all of President Trump's hawkish critics' worst fears about his landmark decision to withdraw US forces from Syria: Namely, that it was made seemingly on a whim, without consulting his national security team, during a phone call with Turkish leader Recep Tayyip Erdogan.

The play-by-play of the call, which was strenuously denied by White House officials, who implied that the account had been planted by Turkish agents who were seeking to undermine the president (though they neglected to specify which details in the account were untrue).

It began by explaining how Trump's aides had prepared detailed talking points for a Dec. 14 call with Erdogan. But Trump abandoned them shortly after it began after apparently being convinced by Erdogan's argument that ISIS had effectively been defeated, given that the once-powerful faction now controls less than 1% of its former territory.

The call had been set up by the NSC after Erdogan threatened to attack US-backed Kurdish troops in Northern Syria whom the Turkish leader accused of supporting the Kurdish independence movement in Turkey.

Trump's advisors had coached him to offer Erdogan a small concession, like holding territory on the Turkish-Syrian border. But after the call began, Erdogan put Trump on the defensive.

"The talking points were very firm," said one of the officials, explaining that Mr Trump was advised to clearly oppose a Turkish incursion into northern Syria and suggest the US and Turkey work together to address security concerns. "Everybody said push back and try to offer (Turkey) something that’s a small win, possibly holding territory on the border, something like that." Mr Erdogan, though, quickly put Mr Trump on the defensive, reminding him that he had repeatedly said the only reason for US troops to be in Syria was to defeat IS and that the group had been 99% defeated. "Why are you still there?" the second official said Mr Erdogan asked Mr Trump, telling him that the Turks could deal with the remaining IS militants.

Erdogan swiftly persuaded the president to come around to Turkey's (admittedly reasonable) point of view: If ISIS had been defeated - and the US's primary objective for its incursion into Syria accomplished, then what were US troops still doing camped out on his boarder?

Mr Erdogan, though, quickly put Mr Trump on the defensive, reminding him that he had repeatedly said the only reason for US troops to be in Syria was to defeat IS and that the group had been 99% defeated. "Why are you still there?" the second official said Mr Erdogan asked Mr Trump, telling him that the Turks could deal with the remaining IS militants.

The deciding factor came when Trump turned to National Security Advisor John Bolton to ask if what Erdogan was saying was true. Bolton then begrudgingly admitted that much, before trying to explain that US forces needed to remain in Syria to prevent a resurgence of ISIS (and to serve as a buffer between the Kurds and a massacre by Turkish troops.

When Trump agreed to Erdogan's suggestion that US troops withdraw, both Erdogan and Bolton were shocked, according to the AP'ssources. But in the following days, the president refused to be dissuaded.

With Mr Erdogan on the line, Mr Trump asked national security adviser John Bolton, who was listening in, why American troops remained in Syria if what the Turkish president was saying was true, according to the officials. Mr Erdogan’s point, Mr Bolton was forced to admit, had been backed up by Mr Mattis, Mr Pompeo, US special envoy for Syria Jim Jeffrey and special envoy for the anti-IS coalition Brett McGurk, who have said that IS retains only 1% of its territory, the officials said. Mr Bolton stressed, however, that the entire national security team agreed that victory over IS had to be enduring, which means more than taking away its territory. Mr Trump was not dissuaded, according to the officials, who said the president quickly capitulated by pledging to withdraw, shocking both Mr Bolton and Mr Erdogan.

In the days since Trump's decision, national security hawks have warned that by withdrawing its troops, the US would effectively cede Syria to ISIS (or Russia, or some kind of Russia-ISIS hybrid). But the reality remains that the alternative advocated by many of Trump's critics (Mattis included) resembles another "forever war", where US troops remain in place not to fight an active enemy, but to ensure that an enemy never reemerges. US troops first arrived in Syria in 2015 about a year after the US began a campaign of airstrikes against ISIS targets in Iraq and Syria.

And how does one defeat an enemy that doesn't exist?