WATCH: Biden Cuts Down Trump's Hostage Claims With a Few Short Words

Joe Biden had a quick response for a reporter who asked about Donald Trump's claims that he could have returned the hostages taken by Russia without giving up anything in exchange. 

Donald Trump has long pushed his relationship with the brutal dictator and murderer Vladimir Putin as some kind of a positive thing. Putin didn't make Trump look very good today, though, when he gave Joe Biden a political win by agreeing to a prisoner exchange. 

The President was speaking to reporters about the details of the exchange when a journalist asked, "Mr. President, when Germany asked for in response for their cooperation —," Biden cut him off responding, "nothing."

The journalist pressed, "President Trump has said repeatedly that he could have gotten the hostages out without giving anything in exchange. What do you say to that? What do you say to President Trump now, the former president?"

Biden responded simply, "Then why didn't he do it when he was President."

Later CNN's Dana Bash played a clip of the moment on CNN and explained, "I think that was what they call a mic-drop moment at the end there. Why didn’t he do it when he was president? What a historic moment. Watching and listening. President Biden, now trying to finish out his one and only term and doing so with, a tremendous, tremendous victory for these families of these people who were held, he said “innocently.”