The quid pro quo didn't just happen. It happens "all the time."

During a Thursday press conference, Acting White House Chief of Staff Mick Mulvaney said Ukraine's disproven involvement with the 2016 DNC email hack played a role in why the U.S. withheld security aid for Ukraine. And when ABC News' Jon Karl explained that Mulvaney had just admitted to a quid pro quo, he simply responded with "we do that all the time with foreign policy."

Trump's camp has claimed there was "no quid pro quo" in his call with Ukraine's president Volodymyr Zelensky, and that security aid for Ukraine wasn't held up because Zelensky didn't move to probe former Vice President Joe Biden. But the administration has still neglected to answer just why that aid was withheld — until Mulvaney's admission Thursday.

"The look-back to what happened in 2016 certainly was part of the thing that [Trump] was worried about" when deciding whether to release aid to Ukraine earlier this year, Mulvaney said, referring to Trump's belief that Ukraine had something to do with the DNC hack. He later said it had nothing to with Biden, and then told the gathered reporters to "get over it" when it came to the admitted quid pro quo. Kathryn Krawczyk