Washington University has been selected by the Commission on Presidential Debates to host more presidential and vice-presidential debates than any other institution in history. United States presidential election debates were held at the Washington University Athletic Complex in 1992, 2000, 2004, and 2016. A presidential debate was planned to occur in 1996, but owing to scheduling difficulties between the candidates, the debate was canceled. The university hosted the only 2008 vice presidential debate, between <answer>Republican Sarah Palin and Democrat Joe Biden</answer>, on October 2, 2008, also at the Washington University Athletic Complex.
Who were the candidates in the vice presidential debate at Washington University?
Republican Sarah Palin and Democrat Joe Biden