December the 14th.
If on December 14, the Electoral College fails to elect a president, then the Constitution also provides for this scenario. Per the 12th Amendment to the Constitution, in this case, the President and Vice President will be elected by the House of Representatives (however, if for some reason the Vice President cannot be elected by the House of Representatives, then the right of his choice is transferred to the Senate.)
clock starting on 11/15? Done in 30?