Sondland, Volker and Vindman are key figures in the House impeachment inquiry into President Donald Trump. Sondland has acknowledged delivering a quid pro quo message to Ukraine, while Volker had numerous dealings with Trump’s personal lawyer, Rudy Giuliani. Testimony from Vindman, the Director for European Affairs at the National Security Council, is also crucial as he was present during the July phone call in which Trump asked Ukrainian President Volodymyr Zelenskiy to investigate the Bidens.
