For just the third time in history, the U.S. Senate has opened a trial to determine if a sitting president should be removed from office. The Senate trial comes a month after the House impeached President Trump for pressuring Ukraine to investigate his political rival Joe Biden. Supreme Court Chief Justice John Roberts, who will preside over the impeachment trial in the Senate, later swore in senators who will serve as jurors when the trial officially begins on Tuesday. This comes as more information is coming to light about the actions of President Trump and his associates. On Thursday, the nonpartisan Government Accountability Office said the White House Office of Management and Budget violated federal law by withholding $400 million in aid money to Ukraine even though the funds had been allocated by Congress. We speak with attorney John Bonifaz, co-founder and president of Free Speech for People and co-author of “The Constitution Demands It: The Case for the Impeachment of Donald Trump.”