What might American foreign policy look like under a Donald Trump presidency? Based on his rhetoric during the campaign, the scale of the departure from the status quo will be profound. He promises to upend long-standing relationships with both America's traditional allies and its foes; he says Europe and Asia should pay more for their own security; and his plans to defeat so-called Islamic State are bellicose but unfocussed. On this week's Newshour Extra, Owen Bennett Jones and his guests take Trump's campaign promises and hold them up to scrutiny. How much of what he's said does he really intend to implement - and will he be able to put policy into practice?