The point was made by Alan Dershowitz, one of the president's attorneys: "If a president does something which he believes will help him get elected in the public interest, that cannot be the kind of quid pro quo that results in impeachment."Asked to respond, Impeachment Manager Adam Schiff was incredulous. "All quid pro quos are fine, it's carte blanche?" Schiff asked. "Is that really what we're prepared to say?"The question of whether witnesses will be included in the trail remains open. While Senate Majority Leader Mitch McConnell told Republicans on Tuesday that he didn't have to votes to block witnesses, Democrats still may not have enough support to subpoena former national security adviser John Bolton. Bolton reportedly claims in a forthcoming book that President Trump conditioned aid to Ukraine on an investigation that would likely benefit his reelection bid.This episode: White House correspondents Tamara Keith and Franco Ordoñez, and political reporter Tim Mak.Connect:Subscribe to the NPR Politics Podcast here.Email the show at nprpolitics@npr.org.Join the NPR Politics Podcast Facebook Group.Subscribe to the NPR Politics Newsletter.Find and support your local public radio station.