He said that Mr. Trump’s plan for a withdrawal could be achieved, but with more time for planning. The 2,000 United States special forces troops in northeastern Syria could be withdrawn and replaced with a new mission and a smaller force to ensure the Islamic State did not resurface and prevent the Syrian government and Iranian forces from taking over the territory, he said.
Mr. Graham has long criticized the United States’ policy of arming and training the Kurdish People’s Protection Units in Syria, also known as Y.P.G., saying that it works against the interests of Turkey, which is a strategic ally of the United States and NATO. The Y.P.G. is affiliated with the Kurdistan Workers’ Party in Turkey. The United States and Turkey have both designated that group a terrorist organization, saying that it works against the interests of Turkey, which is a strategic ally of the United States and NATO.
To withdraw and leave the Kurdish fighters with weapons supplied by the United States was “insane,” the senator said.
Turkey would be driven to take military action inside Syria, creating a broader war, he said. “That would be putting Turkey in a terrible spot,” he said in an interview ahead of the briefing. “That can all be avoided if we slow this down.”
Gen. Joseph F. Dunford, the chairman of the Joint Chiefs of Staff, has a plan, he added. American forces would maintain control of air space in eastern Syria, and other international forces could continue support for the Syrian Democratic Forces, which have been working with American forces to combat the Islamic State. Both France and Britain have units in Syria.
Mr. Graham said the most important step to prevent a broader war and a Turkish invasion was to ensure that the road map for the city of Manbij in northern Syria went ahead. Under that plan, Y.P.G. forces would withdraw and a local council acceptable to all sides, including Turkey, would take over the city’s administration.
The United States could move away from what Mr. Trump has called the “endless war” but still meet national security objectives to “protect an ally from a problem it created,” he said.
“You can do all that with smaller forces, partnering with others,” Mr. Graham added. “It would be a new mission, but the idea that Syria is not strategically important to the United States I completely reject.”