Donald Trump is back and heading for an epic election rematch with Joe Biden in November. So how is a man facing 91 charges and four different criminal trials managing to defy the laws of political gravity? Is he on course to retake the White House, or could judges or swing voters stop him? In a Panorama collaboration with the Americast podcast on BBC Sounds, Justin Webb and Marianna Spring travel from the frozen plains of Iowa to the crucial swing state of Georgia to explore Donald Trump’s enduring appeal and look ahead to an unprecedented American election year.