On the eve of the most important US midterm elections for a generation, Panorama examines allegations that Trump colluded with Russia to win the presidency, and looks at the similarities with the Watergate scandal which brought down Richard Nixon. Reporter Hilary Andersson joins the campaign trail in West Virginia, where the president's message of a vast political witch-hunt against him has fired up Republican voters. If the Democrats do well tomorrow, it could open the door to impeachment, but Trump's supporters believe they will win and warn of riots should the establishment try to take their man down.