This Friday the Senate is expected to vote on whether to call witnesses to testify in the impeachment trial of U.S. President Donald Trump. If they vote yes, it would mean that next week Trump will deliver his annual State of the Union speech while being tried for his removal from office. Two American presidents have delivered state of the union addresses under threat of impeachment: Democrat Bill Clinton and Republican Richard Nixon. White House Correspondent Patsy Widakuswara looks at how the two presidents handled their speeches and what Trump might learn from them.