More than 50 Democratic House members issued an open letter Wednesday to President Trump saying his decision to withdraw U.S. troops from northeastern Syria in advance of a Turkish military operation puts U.S. allies in danger, jeopardizes U.S. counterterrorism efforts in the region and will cause “current and future allies to question the reliability of the U.S. as a partner.”

Signers of the letter include a wide spectrum of political views within the party, from the left, to moderates, combat veterans such as Reps. Jason Crow (D-Colo.), who spearheaded the effort, and former CIA officers Abigail Spanberger (D-Va.) and Elissa Slotkin (D-Mich.), who won in a district Trump carried in 2016.

The letter came as Republican lawmakers, who have been widely critical of Trump’s action, chastised Democrats for not speaking out.

Crow and Spanberger were among a bipartisan group of lawmakers who returned Monday from a congressional visit to Turkey, Afghanistan and the Syria-Jordan border, as news of the U.S. withdrawal was breaking.

Crow, a member of the House Armed Services Committee, is a former army Ranger who served three tours in Iraq and Afghanistan. He and Spanberger returned Monday from a bipartisan congressional visit to Turkey, Afghanistan and the Syria-Jordan border, as news of Trump’s withdrawal decision was breaking.

“We believe your decision … will have far-reaching diplomatic and national security implications,” the letter to Trump said. “It will dramatically alter our partnership with the Syrian Democratic Forces,” the Syrian Kurdish-dominated militia that has partnered with the United States against the Islamic State, “allow unilateral Turkish incursions into Syria, and jeopardize” the effort to eliminate the Islamic State.

In a list of questions posed to the president, the lawmakers asked what advance planning the administration had done to ensure counterterrorism operations in Syria continue.

“This decision jeopardizes decades of trust in American solidarity and will only serve to undermine current and future alliances,” it said.