Sen. Lindsay Graham (R-S.C.) defended the firing of National Security Council (NSC) Ukraine expert Lt. Col. Alexander Vindman Alexander VindmanImpeachment witness Alexander Vindman calls Trump Putin's 'useful idiot' The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Trump, Biden renew push for Latino support Strzok: Trump behaving like an authoritarian MORE, suggesting he may have been involved in leaking information to the whistleblower whose complaint prompted President Trump Donald John TrumpHR McMaster says president's policy to withdraw troops from Afghanistan is 'unwise' Cast of 'Parks and Rec' reunite for virtual town hall to address Wisconsin voters Biden says Trump should step down over coronavirus response MORE’s impeachment.

“I think his reassignment was justified, I don’t think he could be effective at the NSC,” Graham said on CBS’s “Face the Nation” on Sunday. “What have I learned in the last two years? CIA agents, Justice Department lawyers, FBI agents have a political agenda and they acted on it, as did Col. Vindman.”

“He was not allowed to be asked questions about his connections to the alleged whistleblower,” Graham added, with host Margaret Brennan pointing out that Vindman was asked and denied any such connections.

Graham also said people in Vindman's "chain of command have been suspicious of him regarding his political point of view.”

Brennan countered that White House national security adviser Robert O’Brien recently said he was satisfied there were no leaks within the NSC.

“Well, I am not,” Graham responded, saying he appreciated Vindman's service, but comparing him to the intelligence officials who “took the law into their own hands.”

“I don’t know what role he played with the whistleblower, if any, but we’re going to look,” Graham continued.

Graham also defended the recall of Ambassador to the European Union Gordon Sondland Gordon SondlandGOP chairman vows to protect whistleblowers following Vindman retirement over 'bullying' Top Democrat slams Trump's new EU envoy: Not 'a political donor's part-time job' Trump names new EU envoy, filling post left vacant by impeachment witness Sondland MORE Friday, pointing out that ambassadors serve at the pleasure of the president.

Both Vindman and Sondland testified in the impeachment proceedings against Trump.