Sarah Montague speaks to US Senator Lindsey Graham at the annual Ambrosetti Forum where thinkers and politicians are meeting to discuss the issues facing the world - including the US presidential election.

Senator Graham, himself a former presidential candidate, is a major critic of Donald Trump and believes the Republican Party should cease to endorse him as their candidate. Graham has warned that Trump has no understanding of the world and is not fit to lead - so what happens if he ends up as America's president? Show less