Sticky impeachment trial questions: How long? Who testifies?

WASHINGTON • What will the impeachment trial look like?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.Presiding will be Chief Justice John Roberts — that's in the Constitution — and theoretically he could issue key rulings on some of these questions. B