Read Kurt Volker's opening statement in the impeachment hearing

Former U.S. special envoy to Ukraine Kurt Volker testified Tuesday in the second public impeachment hearing of the day.

Why it matters: Volker was part of a cadre of officials who worked with Rudy Giuliani to push Ukraine to announce investigations into Trump's political rivals, but he maintains that he never believed those investigations to include Joe Biden. In one major change from his closed-door deposition, Volker said in his opening statement that EU Ambassador Gordon Sondland brought up "investigations" in a meeting with Ukrainian officials at the White House.