Senator Chuck Grassley (R-IA), the president pro tempore of the U.S. Senate, swears in U.S. Supreme Court Chief Justice John Roberts to preside over the Senate impeachment trial of U.S. President Donald Trump in this frame grab from video shot in the Senate Chamber at the U.S. Capitol in Washington, U.S., January 16, 2020. REUTERS/U.S. Senate TV/Handout via Reuters
