Sticky impeachment trial questions: How long? Who testifies?

(Mark Humphrey | AP) In this Feb. 6, 2019 file photo, Supreme Court Chief Justice John Roberts answers questions during an appearance at Belmont University in Nashville, Tenn. How a Senate impeachment trial of President Donald Trump would unfold is not yet known, but among the issues senators will have to decide are how long it lasts and whether witnesses are called. Presiding over the trial will be Chief Justice John Roberts, who theoretically could issue key rulings on some of these questions. While a Senate trial of President Donald Trump now appears inevitable, details of how it will unfold remain unknown. How long will proceedings last? Can either party summon witnesses to make its points? Senators will have to decide these and other, potentially thorny questions.

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