7 Things to Know About How a br Senate Impeachment Trial Works.br 1. Senators take an oath br to "do impartial justice.".br Though Senate majority leader br Mitch McConnell has stated, "I'm not an br impartial juror," the wording of the required br Constitutional oath is clear on the necessary impartiality.br 2. A majority is needed br in order to call a witness.br President Donald Trump has br indicated he'd like the whistleblower br to be called as a witness, but more moderate br Republicans could prevent such an occurrence.br 3. Restrictions exist on who br the TV cameras can focus on.br Rules agreed upon in 1986 br state that cameras can only br focus on the person speaking.br 4. Much of the discussion br could occur behind closed doors.br During former President Bill Clinton's br impeachment trial, many of the senators'br speeches took place on camera, but br deliberations on voting often occurred in private.br 5. The first and last br word goes to the accusers.br Rule XXII states that the br "argument shall be opened and br closed by the House of Representatives.".br 6. Witnesses may be br deposed on video or in private.br During Clinton's impeachment trial, br the star witness, Monica Lewinsky, was br deposed on video with portions of the br deposition being played during the trial.br 7. Only 34 senators are br required to acquit President Trump.