Televised impeachment hearings begin today in the inquiry into whether President Trump withheld military aid from Ukraine to pressure the Ukrainian president to investigate his political rival Joe Biden and his son. Two witnesses are testifying today before the House Intelligence Committee: George Kent, a deputy assistant secretary of state, and William Taylor, a former ambassador and the top U.S. diplomat in Ukraine.

Both officials have privately told congressional investigators that Trump withheld aid to Ukraine in an attempt to pressure Ukraine to investigate the Bidens. In now-released text messages, Bill Taylor texted Gordon Sondland, the U.S. ambassador to the European Union and a wealthy hotel magnate, “Are we now saying that security assistance and White House meeting are conditioned on investigations?” Sondland texted back, “Call me” — perhaps not wanting to leave a paper trail. Today marks only the third televised impeachment hearings in U.S. history. We’ll have more on today’s historic hearings after headlines with legendary journalist Bill Moyers, who covered the Nixon and Clinton impeachment hearings.