Sen. Patrick Leahy (D-Vt.), president pro tempore of the Senate, will preside over next month’s impeachment trial of former President Donald Trump, Leahy said on Jan. 25. Leahy is 80. Both parties traditionally choose their eldest member to serve in the pro tempore role, which is essentially a backup for the president of the Senate, whenever they gain a majority in the body. “The president pro tempore has historically presided over Senate impeachment trials of non-presidents,” Leahy said in a statement. “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. It is an oath that I take extraordinarily seriously. “I consider holding the office of the president pro tempore and the responsibilities that come with it to be one of the highest honors and most serious responsibilities of my career,” he said. “When I …