President Donald Trump has revealed more details of his controversial turnaround on Syria, linking his decision to withdraw U.S. troops from the country to his relationship with Turkey’s controversial President Recep Tayyip Erdogan.

Erdogan “has very strongly informed me that he will eradicate whatever is left of ISIS in Syria....and he is a man who can do it,” Trump wrote on Twitter on Sunday night. “Plus, Turkey is right ‘next door.’ Our troops are coming home!”

An earlier tweet from Trump mentioned that the two leaders had a call that dealt with Syria as well as trade, a top issue for him. And a conversation with Erdogan on Dec. 14 was central to Trump’s Syria move, The Associated Press reported, after Erdogan asked why U.S. forces still needed to be in the country, given the success of efforts against the ISIS insurgency there. Trump’s sudden agreement on that point caught Erdogan “off guard,” according to the AP, and Trump quickly directed top aides to start arranging a drawback ― a policy shift that almost no one in his national security circle supported and that led to the resignations of Defense Secretary Jim Mattis and top State Department official Brett McGurk.

It’s true that bombing and ground support for local partners by the U.S. and allies since 2014 has drastically shrunk the ISIS presence, which mushroomed amid Syria’s civil war. Meanwhile, Trump’s political rise and presidency have been associated with politically popular criticism of U.S. intervention abroad ― this is something he can say he has delivered on to his voters ― and he has received some praise for the decision from detractors of the national security establishment like Sen. Rand Paul (R-Ky.).

But critics of the decision have gained traction by highlighting the rushed way it seems to have been made over the objections of Trump’s advisers, and the Sunday message helps them by suggesting that he is to at least degree being guided by his long-running fixation with strongmen. Using “strongly” and saying Erdogan “is a man who can do it” echoes Trump’s previous niceties about the Turkish president, who has jailed dozens of journalists, and Russian President Vladimir Putin ― and hints more at a feeling than a sober national security assessment.

From a strategic viewpoint, betting on Erdogan in such a big way is risky. His priorities in Syria don’t neatly align with those of the U.S.: While Washington prioritized weakening ISIS, he helped with that fight but was largely fixated on Kurdish militants who also became stronger as Syria fell into chaos. American policymakers have been supporting the Kurdish People’s Protection Units, or YPG, which Erdogan dislikes and is ideologically linked to a rebel group that has battled the Turkish government for decades. For him, taking on a larger role in Syria will likely mean trying to curtail the Kurds’ power.

Additionally, Erdogan’s past relationship with ISIS is murky. While his government has targeted by the group and has cracked down on its networks in Turkey, for years it turned a blind eye to the flow of fighters and money to extremist groups involved in the opposition to Syrian President Bashar Assad, whom Erdogan wanted to see ousted.

The Turkish leader has softened on Assad but continues to support fighters in Syria who may have turned on the formerly U.S.-backed Kurds. And in the course of adjusting his Syria policy and dealing with other issues like Western criticism of his record on human rights, Erdogan has grown closer and closer to Putin ― a problem for the leader of a NATO member country and another reason U.S. officials are wary of fully following the Turkish lead.

Trump’s latest message will likely only fuel a controversy that now has even commentators close to his administration publicly fretting.

“Republicans blasted Obama for cozying up to Erdogan before he finally woke up to the threat Erdogan represented to American interests,” Mark Dubowitz of the hawkish think tank Foundation for Defense of Democracies wrote on Twitter, referring to the way President Barack Obama’s initial outreach to Erdogan ultimately devolved into distrust between the two. “Now, it’s Trump turn for self-delusion.”