Republicans in Congress assailed President Donald Trump's decision to withdraw US troops from Syria's border with Turkey on Monday, warning that a threatened Turkish invasion would lead to a dangerous resurgence of the Islamic State, the slaughter of US allies in the region and a boon for American adversaries.
Calling the decision "a major blunder," Sen. Lindsey Graham, R-SC, usually a staunch defender of Trump's foreign policy, said in an interview that it was "an impulsive decision that has long-term ramifications" and "cuts against sound military and geopolitical advice."
Senate Majority Leader Mitch McConnell, R-Ky, urged Trump to "exercise American leadership" and warned that "a precipitous withdrawal" would benefit Russia, Iran and Syrian President Bashar Assad, and increase the risk that the Islamic State would "regroup."
Some senior officials at the Pentagon said they were blindsided by the decision, the second time in less than a year that Trump has upended U.S. strategy in Syria after a telephone call with Turkish President Recep Tayyip Erdogan.
Defense officials and observers on the ground said the small contingent of U.S. forces had already begun withdrawing from the border area. The troops were participating in joint patrols under a US-Turkish agreement to establish a safe zone on the Syrian side that now appears to be moot.
A senior administration official, who spoke to reporters on the condition of anonymity, said the 50 to 100 troops in the safe-zone area would be redeployed elsewhere in Syria.
Military officials stressed that they would not provide any assistance to Turkish forces or the US-allied Syrian Kurds whom Turkey has demanded leave the area. The Kurdish forces, who are lightly armed compared with the Turkish military, have fought alongside Americans for years.
One official said Americans overseeing coalition air operations over Syria, which have been conducted by a number of allied nations in addition to the United States, had stopped providing intelligence information to Turkey related to the flights and had removed Turkey from the roster of countries taking part in that mission.
By nightfall, despite Erdogan's pledge to begin an air and ground assault on Kurdish areas, Turkish troops did not appear to have advanced. A defense official said that the U.S. military was aware of apparent bombing or shelling by Turkish forces but that it appeared to be outside the safe zone.
In a tweet Monday afternoon, Trump seemed to have second thoughts, warning that "if Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey."
At the State Department, another senior official authorized to brief reporters on the condition of anonymity denied suggestions that Trump had endorsed a Turkish incursion. "We do not support this operation in any way, shape or form," according to the official, who said Trump rejected an appeal from Erdogan for military assistance.
Top officials, including Defense Secretary Mark Esper, said as recently as last week that they were committed to making the "security mechanism" work, a reference to the presence of US personnel in the safe zone and joint patrols.
The US troop presence in eastern Syria has provided a symbolic bulwark against Turkish incursions, as well as expansion by Assad's forces and his Russian and Iranian allies into areas that Kurdish and US troops have cleared of the Islamic State. In addition to concern about a militant resurgence, US military officials have expressed a sense of loyalty to the Kurds.
That sense of loyalty was an important factor in Defense Secretary Jim Mattis's decision to resign in December after Trump - following a conversation with Erdogan - abruptly decided to withdraw all US forces from Syria. That decision was later walked back, though the number of US troops was reduced from about 2,500 to about 1,000.
Last month, as the United States and Turkey traded recriminations over Ankara's purchase of an advanced Russian air defense system and haggled over the safe zone, the two governments continued to promote the idea that shared commercial interests could bridge their disagreements.
During a visit to Ankara in September, Commerce Secretary Wilbur Ross said he had had an "especially productive meeting" with Erdogan that included discussions about Trump's proposal to generate up to US$100 billion in trade between the two countries.
Sunday's call between the two leaders originated as a conversation about the air defense issue and economic cooperation.
"Erdogan then raised going into northeast Syria, claiming that the safe zone mechanism that we'd set up and were executing was not meeting his needs and he wanted to do a unilateral operation," the State Department official said. But "there was no specific indication at this time he would push the button, and we still don't know in the end what he's going to do."
Trump's tweet about "obliterating" the Turkish economy did not indicate what conditions he believed would merit such a response. Asked about a possible Turkish massacre of the Kurds, the senior administration official emphasised that Trump's main concern was the safety of US personnel but insisted that "the president has made it very clear there should be no untoward action with respect to the Kurds or anyone else."
In a Sunday White House statement and Monday's tweets, Trump suggested that the United States was shouldering too much of the burden - and the cost - of fighting the Islamic State.
He also retweeted an assertion that the Syrian Kurds are akin to Turkey's own Kurdish autonomy movement, which both Turkey and the United States have labeled a terrorist group. That stance, part of Turkish dogma and the rationale for its planned attack, has been anathema to US policy for years, especially since Syrian Kurdish fighters have served as the primary ground force against the Islamic State, with the United States providing logistical and air support. The Kurds have suffered more than 10,000 casualties in the fight.
The fast-moving developments threatened a fresh military conflagration in a large swath of northern Syria, where Ankara has been increasingly unnerved by the Kurdish presence and close US ties to the fighters.
Erdogan has been threatening an imminent invasion for months, both to create a buffer against the Kurds and to provide a place where Turkey can relocate some 3.5 million Syrian refugees who have fled over the border.
The Trump administration believed that the safe-zone agreement would satisfy Turkish security demands and provide a measure of protection for the Kurds so they would continue to spearhead the ground fight against Islamic State forces, which have dispersed in Syria and Iraq. But Turkey has repeatedly complained that the zone is too small and US implementation is too slow.
Despite what his own diplomats have negotiated, Trump "just wants out" of Syria in general, said an adviser who has repeatedly discussed the issue with him. "He doesn't want to be there. He doesn't want to pay."
"He doesn't believe any of his advisers that tell him that [the Kurds] are in jeopardy, that Erdogan will kill them," the Trump adviser said. "The president has always professed to believe that Turkey and Erdogan's . . . massive military capability can contain ISIS" and protect the eastern region from Assad and his allies, despite US military warnings to the contrary.
A White House statement Sunday night said that if the Turks chose to move into Syria, they - and countries in Europe and elsewhere - would be responsible for fighting the Islamic State and guarding thousands of militant prisoners the Kurds are holding in eastern Syria.
In his tweets, Trump criticized European governments that have largely refused to repatriate their own citizens who are among the captured Islamic State fighters.
In a statement Monday in Paris, French Defense Minister Florence Parly said that "we will be paying extremely close attention as to whether this announced US withdrawal, as well as a potential Turkish offensive, create a dangerous diversion" that allows an Islamic State resurgence.
France's position on repatriating prisoners, she said, "has not changed. We believe that those who committed crimes in [Syria] must be prosecuted in that country. Our position is unwavering. I am not saying anything new, just as the United States is not saying anything new."
The United Nations has also objected to Turkey's plans to relocate refugees, saying international law allows repatriation - unless agreed by the refugees themselves - only to the places they came from in the first place. A relatively small fraction of the Syrians in Turkey are from the arid border region.