What To Know About The 4 Witnesses Testifying Tuesday In Impeachment Inquiry

Democrats open the second week of public hearings in the impeachment inquiry with testimony from Lt. Col. Alexander Vindman and Jennifer Williams. Each listened to the July 25 call between President Trump and Ukranian President Volodymyr Zelenskiy.

In a separate afternoon session, lawmakers will question Kurt Volker, the former State Department envoy to Ukraine for its peace negotiations and Tim Morrison, a former National Security Council aide.

Here & Now's Robin Young gets the latest on the impeachment inquiry hearings from Michele Kelemen (@michelekelemen), who covers the State Department for NPR.