Stephen Sackur speaks to American constitutional law professor Laurence Tribe. It is a year since pro-Trump protestors stormed the US Capitol and unleashed a spasm of violence which left five people dead. While hundreds of people have since been charged, none have been key associates of Donald Trump. Mr Trump seems to be contemplating another run for the White House and is still insisting, without evidence, that the 2020 election was stolen. Professor Laurence Tribe contends that the US system of government is now in peril. How strong is his case? Show less