"The president pro tempore has historically presided over Senate impeachment trials of non-presidents. When presiding over an impeachment trial, the president pro tempore takes an additional special oath to do impartial justice according to the Constitution and the laws," Leahy said. Politico last week reported that Roberts "wants no further part" in overseeing an impeachment after he presided over Trump's impeachment trial one year ago. TRUMP IMPEACHMENT ARTICLE BEING SENT TO SENATE MONDAYThe chief justice of the United States is constitutionally required to oversee impeachment trials of sitting presidents. In almost all cases, the vice president and the Senate president pro tempore are interchangeable as far as who oversees Senate business.

Source: Fox News January 25, 2021 19:42 UTC