Sen. Lindsey Graham told "Axios on HBO" last month that he'd be open to changing his mind on impeachment if he was shown Trump was engaged in a quid pro quo with Ukraine outside of the July 25 phone call.

Why it matters: Today, EU Ambassador Gordon Sondland publicly testified in an impeachment hearing that a quid pro quo preconditioning a White House meeting in exchange for an investigation into the Biden family's business dealings in Ukraine took place and "reflected President Trump's desires and requirements."

What they're saying:

"If you could show me that Trump actually was engaging in a quid pro quo, outside the phone call, that would be very disturbing"

— Graham in October on "Axios on HBO"

"I know that members of this Committee have frequently framed these complicated issues in the form of a simple question: Was there a 'quid pro quo?' As I testified previously, with regard to the requested White House call and White House meeting, the answer is yes."

— Sondland in his opening statement at a public impeachment hearing

Go deeper: Live updates from Sondland's testimony