U.S. Sen. Angus King, right, poses with Ukraine President Volodymyr Zelenskyy, center, and Rhode Island U.S. Sen. Jack Reed, left, during a visit to Ukraine in a photograph provided by the Ukrainian government. Credit: Courtesy of U.S. Sen. Angus King's office

The U.S. should keep aiding Ukraine until Russian troops have left the country, U.S. Sen. Angus King said Monday shortly after returning from a Kyiv meeting with President Volodymyr Zelenskyy.

“I believe we should remain there until [Russian President Vladimir] Putin is out,” King said at a Monday news conference.

He said providing an exact timetable on U.S. involvement would play into Putin’s hands, but does not envision the conflict becoming a decades-long struggle like that seen in Afghanistan from 2001 to 2021.

King returned Saturday from his two-day visit, which included a meeting with Zelenskyy and other top Ukrainian officials as part of his responsibilities with the Senate Armed Services Committee. U.S. Sen. Jack Reed, D-Rhode Island, who chairs that committee, accompanied him.

The trip came amid increased scrutiny by some of the most conservative members of the new House Republicans majority of the massive aid the U.S. has sent to the country. The conflict is the largest ground war in Europe since World War II.

The aid has added up to more than $20 billion since February, according to the Defense Department, with $1.85 billion more secured by Zelenskyy during a visit to Washington last month. U.S. Rep. Matt Gaetz, R-Florida, a top conservative instigator, has called for aid to be suspended, although a strong House majority still backs Ukraine aid.

King said opposition to assistance among conservatives was “concerning” but did not seem to reflect the Republican mainstream. Senate Minority Leader Mitch McConnell, R-Kentucky, has been a consistent advocate of aid to Ukraine. New House Speaker Kevin McCarthy, R-Califorinia, said in October that House Republicans wouldn’t write a “blank check” to Ukraine if the GOP took the majority, but he has also worked to assure members that he backs aid.

King, an independent who caucuses with Democrats, said it was reasonable to be concerned about accountability, but that what he saw in the country impressed him: Ukrainains were using cutting-edge technology to track international assistance and exactly how it is used. Given the domestic implications, he warned Zelenskyy about the cost of malfeasance.

“I said ‘if there’s a scandal involving the misuse of these resources, that will jeopardize any additional resources flowing,’” King said. “He understood that.”

King met with Zelenskyy for about an hour while wearing a sweatshirt featuring a picture of Brewer-raised Civil War Gen. Joshua Chamberlain. He said he wore the shirt to compare Chamberlain’s heroics and leadership, including at the Battle of Gettysburg, to Zelenskyy’s efforts to maintain Ukrainian sovereignty after Russia’s invasion last year.

“That was a thrilling moment, to meet a person I consider one of the great leaders of this century,” King said.

Expanding on his Sunday appearance on CBS News’ “Face the Nation,” King frequently invoked the lessons of World War II and the deadly consequences of appeasing Nazi Germany under Adolf Hitler in justifying continued support for Ukraine.

“We just have to continue to remind people how important it is and that this is not some faraway conflict that doesn’t involve us,” King said. “That was the same attitude that was in this country in the late 1930s.”