ADVERTISEMENT "The announcement today is being portrayed as a victory. It is far from a victory. Serious questions remain about how the decision was reached precipitously to withdraw from Syria and why that decision was reached," Romney said.

Romney's Senate floor speech came after Vice President Pence announced a five-day cease-fire.

Under the agreement Pence said Turkish President Recep Tayyip Erdoğan agreed to halt Turkey’s offensive in Syria for 120 hours in order to allow Kurdish YPG forces to evacuate. The agreement will also maintain a “permanent cease-fire” once the evacuation is complete.

Romney added the administration needs to explain what the U.S. role will be moving forward. And the cease-fire, he argued, does not change that the United States "abandoned" the Kurds.

"Adding insult to dishonor, the administration speaks cavalierly, even flippantly, even as our ally has suffered death and casualty," Romney said. "We once abandoned a red line. Now we abandon an ally."

"The decision to abandon the Kurds violates one of our most sacred duties. It strikes at American honor. What we have done to the Kurds will stand as a bloodstain in the annals of American history," Romney continued.

Trump's decision to pull back U.S. troops from northern Syria, paving the way for the Turkish invasion, has sparked fierce backlash on Capitol Hill. Lawmakers warned the decision would embolden ISIS and endanger the Kurds, who worked with the United States to combat the terrorist organization.

Trump ran on an isolationist foreign policy campaign in 2016 that puts him at odds with most of the Senate GOP caucus, who lashed out at his decision as "catastrophic," a "grave mistake" and a "disaster in the making."

Trump sparked another round of backlash on Wednesday when he told reporters during a White House meeting that the Kurds were "no angels."

Romney added during his floor speech that the committee was not consulted ahead of Trump's decision.

"I might be forgiven for wondering why our committee even exists," he said.