Washington (CNN) - Republican Sen. Lindsey Graham on Sunday advised President Donald Trump against pulling troops out of Afghanistan, warning of "disastrous" consequences if the US dipped below keeping at least 8,600 troops in the country.
"Mr. President, if you don't have a counter-terrorism force left behind, even if you've got to deal with the Taliban -- which I doubt, but you might -- they don't have the capability or will to protect the American homeland," the South Carolina senator said on CBS' "Face the Nation."
Graham, a Trump ally and frequent voice in the President's ear, said the US troops in Afghanistan are an "insurance policy against another 9/11," adding that the US needs a "robust counter-terrorism force" to ensure terrorist groups ISIS and al Qaeda do not "regenerate" in Afghanistan.
"In one day, we lost 3,000 Americans because we took our eye off the ball in Afghanistan," Graham said. The senator has in the past urged Trump to maintain an American military presence in the country.
Graham's comments come as a US-Taliban peace plan is in the works. The peace plan is expected to formalize a significant withdrawal of US forces from Afghanistan -- from about 15,000 troops to 8,000 or 9,000 troops -- and enshrine official commitments by the Taliban to counter-terrorism efforts in Afghanistan, according to the multiple sources familiar with the plan. The plan could end America's longest running war, but could also trigger a surrender for the US and a betrayal of the Afghan government, critics say.
Trump has repeatedly advocated for bringing US troops back from Afghanistan, putting him at odds with hawkish Republican lawmakers like Graham.
Both Trump and Democrats running for president in 2020 have said they would bring the troops home, but Graham said Sunday, "They're all wrong."
Graham said he is "concerned" that Trump is going to "make the same mistake that President Obama did in Iraq" by pulling out the troops.
"You may get a peace deal with the Taliban, but you'll never get a peace deal with al Qaeda or ISIS," Graham said.
The senator said he was going to introduce legislation requiring the US Secretary of Defense and the US Secretary of State to "certify to the Congress that to go below 8,600 does not create an additional national security risk to the homeland."