Lindsey Graham

HARDtalk's Sarah Montague speaks to US Senator, Lindsey Graham, at the annual Ambrosetti Forum where the world's big thinkers and politicians are meeting to discuss the challenges we face today. They believe the biggest issue in the world for them is what happens in the US presidential election. Senator Lindsey Graham, himself a former presidential candidate, is among them. He has called Donald Trump a "jackass" and says their party, the Republicans, should un-endorse him as their candidate for president. He has warned that Donald Trump has no understanding of the world and is not fit to lead. So what happens if he ends up as America's president?