HARDtalk’s Stephen Sackur speaks to Donald Verrilli, US Solicitor general under Barack Obama. The Trump presidency promises to be a fascinating test of the resilience of the system of government crafted by America's founding fathers. The new president has already criticised the courts for utilising their authority in blocking the so-called travel ban, with a new ban coming into effect imminently. Does the constitution ensure that the White House is always subject to and not above the law?