Stay up to date with notifications from The Independent Notifications can be managed in browser preferences. All News Sport Culture Lifestyle King Charles delivers historic speech to US Congress amid strained US-UK relationship King Charles says US ‘lies at the heart of Nato’ after Trump's repeated threats to leave alliance King Charles addressed a joint session of the US Congress Tuesday, implicitly challenging President Donald Trump 's threats to withdraw the US from NATO by affirming the alliance's importance and highlighting Britain's increased defence spending. During his historic speech , the King underscored the necessity of 'unyielding resolve' for Ukraine's defence, drawing a parallel to the invocation of NATO's Article 5 after the 9/11 attacks. He emphasised the enduring 'special relationship' between the UK and the US, describing their partnership as 'one of the greatest alliances in human history' and more crucial than ever, despite past disputes.…