NPR's Steve Inskeep hosts a special report on the impeachment inquiry. At the center of the impeachment inquiry is a whistle blower's complaint about the President's actions on a call to the president of Ukraine. Did the president abuse his power when he asked for investigation into a political rival? Inskeep, along with NPR's hosts, correspondents, and producers step through the story as we know it so far - explaining who the key players are and what they knew.