On December 19, 2018, U.S. President Donald Trump announced the withdrawal of the U.S. troops from Syria, tweeting that "after historic victories against ISIS, it’s time to bring our great young people home!" Whitehouse spokesperson Sarah Sanders confirmed that the U.S. had begun to pull its troops from the country as part of the transition to the next phase of the campaign.
This announcement by Trump came as a surprise inter alia because it is completely at odds with statements made by U.S. officials in the past weeks. For example, U.S. special envoy to the international coalition fighting ISIS Brett McGurk said only a week ago that liberating ISIS's remaining stronghold in Syria could take several months, and assessed that "Americans will remain on the ground after the physical defeat of the [ISIS] caliphate, until we have the pieces in place to ensure that that defeat is enduring." 
At a press conference on the margins of a December 3, 2018 conference of the Small Group on Syria in Washington, D.C., U.S. Special Representative for Syria Engagement Amb. James Jeffrey stated that the U.S. would withdraw its troops from Syria only after the Islamic State (ISIS) was defeated, the Iranian military presence had left Syria, and a political arrangement in Syria had been attained. He added that the talks on Syria that were part of the Russia-, Turkey-, and Iran-backed Astana conference had failed, as had the Russia-Turkey talks in Sochi, and that the U.S. saw a need to go back to the outline set out by the UN-backed Geneva conferences.
Additionally, following his December 7, 2018 meeting with Turkish officials, Amb. Jeffrey clarified that the U.S. had "no problem" with the Astana and Sochi talks, sponsored by Russia, Turkey and Iran, but that these processes, like the processes backed by the UN, had failed because of the actions of the Syrian regime.
These statements by Amb. Jeffrey were met with harsh criticism of him on the part of the Syrian regime. Articles in the Syrian government press stated that he was unfit for his mission, and called him "pathetic and disconnected from reality." Along with reiterating the familiar claims that it is the U.S. that is supporting ISIS and terrorism in Syria, the articles added that the U.S. "is in no shape" to set conditions regarding the presence of its forces in Syria, and that it cannot pay what it would cost to remain there.
The following are translated excerpts of two of these articles:
Amb. James Jeffrey (source: usembassy.gov)
Syrian Columnist: The U.S. "Cannot Pay What It Would Cost" To Remain In Syria – And Its Conditions Are Unacceptable
In his December 6, 2018 column in the Syrian government Al-Thawra daily, 'Ali Nasrallah addressed Jeffrey's statements, calling the ambassador "pathetic and disconnected from reality." About the conditions he set out for a U.S. withdrawal from Syria, Nasrallah said that the U.S. is in no shape to set conditions and that the ambassador was daydreaming. Nasrallah wrote:
"James Jeffrey, who took up his role as American special envoy for the Syrian issue, and his colleague Brian Hook, who at the same time began serving as [U.S.] Special Representative for Iran, have a great deal of experience in cheap, obvious hypocrisy – like all the [U.S.] State Department officials who preceded them since the 1970s. Thus, it is clear that people such as Jeffrey or Hook are not fit for the difficult mission with which they are charged...
"This Jeffrey is pathetic and disconnected from reality, with his reiteration not only of what has become ridiculous, but also of what increases the loathing towards every American and everything American. This arouses ridicule of the U.S. not only as a political regime but also as a contemptible, bullying force that thinks that others are stupid and denigrates their intellectual capabilities...
"How can the U.S., [which is] up to its neck [in trouble in Syria, dare] set conditions – none of which will be met?! It is drowning, but is up a tree from which it cannot come down. Is the U.S. in any shape to set [these] absurd conditions?...
"Jeffrey, the U.S. definitely will not remain in Syria forever – not because it doesn't want to, but because it cannot pay what would cost to do so. Perhaps soon it will need time to pack its bags and leave, but it will not have [that time].
"Jeffrey, you [i.e. the U.S.] will not manage to protect ISIS, which the Syrian army and its allies have defeated, once [this army] gets rid of the problem of terrorism in Idlib, which you also support.
"Jeffrey, it is none of your business if Iran, [our] ally and strategic partner, has forces or advisors in Syria... This is a sovereign matter that concerns Damascus and Tehran, whose relations will deepen. With regard to the political process itself, these [demands of yours] are daydreams. Continue with your nonsense. We will wait and see."
Another Syrian Columnist: The U.S.'s "Talk Of Remaining In Syria... Won't Help It" – It Must Cut Its Losses In Syria And Leave
In a similar vein, another Al-Thawra columnist, Hussein Saqr, advised the U.S. to cut its losses and leave Syria as quickly as possible. He wrote:
"The resounding failure of the American policy in Syria attests to the fact that the [Syria] strategy drawn up by the U.S. eight years ago has completely failed, and it also clearly shows the scope of the disagreement among its senior officials. [Proof of this is reflected] particularly in [their] contradictory statements vis-à-vis remaining in or leaving Syria after the elimination of the ISIS terrorist organization, whose interests are protected by the current American administration as they were by previous [American administrations].
"Eliminating ISIS and the other terrorist organizations was never an American aspiration. The presence of these organizations assists the attainment of the West's goals, first and foremost the preservation of access in and out of Syria, the protection of the military bases established by the U.S. in the region to serve its [interests], the continuation of [the U.S.'s ability] to run roughshod over and intimidate the rulers of the countries that pay it protection money, and [the continuation of its ability] to protect Israel...
"It is usual for the U.S. to talk of vague plans and release ambiguous statements that can be understood several ways. But the upshot is the same, and its hidden intentions are known, and it is a broken record. Its talk of remaining in Syria and of a repeat of the Iraq scenario won't help it, nor will a continuation of its support for terrorists. Its call for ending the Astana and Sochi initiatives will gain no traction. Only one thing will help it – and that is cutting its losses and leaving the scene...
"The U.S.'s remaining in Syria will complicate matters, deepen the crisis that it [i.e. the U.S.?] is in, extend the duration of the war, and disrupt the solutions that have been proposed. This is because it [the U.S.?] continues to thwart and throw monkey wrenches [into the works] of the longed-for peace and security to which the Syrians aspire."
 Twitter.com/realDonaldTrump, December 19, 2018.
 Reuters.com, December 19, 2018.
 State.gov/s/seci/2018/288160.htm, December 11, 2018.
 On January 23, 2018, the Small Group, comprising Egypt, France, Germany, Jordan, Saudi Arabia, the United Kingdom and United States, drew up a document of principles for a solution to the Syria crisis, which was conveyed to UN Envoy for Syria Staffan de Mistura.
 Jeffrey made similar statements in a September 26, 2018 interview with the London-based Saudi daily Al-Sharq Al-Awsat. See MEMRI Special Dispatch No. 7687, U.S. Special Envoy For Syria James Jeffrey In Interview With London Arabic Daily 'Al-Sharq Al-Awsat': No U.S. Goal To Oust Assad; U.S. Forces In Syria Tasked With Defeating ISIS, Guaranteeing Withdrawal Of Iranian Forces, September 27, 2018.
 State.gov/r/pa/prs/ps/2018/12/287752.htm, December 3, 2018.
 Hurriyet (Turkey), December 8, 2018.
 Al-Thawra (Syria), December 6, 2018.
 Al-Thawra (Syria), December 6, 2018.