Dutch Prime Minister Mark Rutte has been appointed Nato Secretary General as the war in Ukraine rages on and uncertainty hangs over the United States’ future attitude to the transatlantic alliance.Mr Rutte’s appointment was a formality after his only rival for the post, Romanian President Klaus Iohannis, announced last week that he had quit the race, having failed to gain enough support.”The North Atlantic Council [Nato’s main political decision-making body] decided to appoint Dutch Prime Minister Mark Rutte as the next Secretary General of Nato, succeeding Jens Stoltenberg,” the alliance announced.”Mr Rutte will assume his functions as Secretary General from 1 October 2024, when Mr Stoltenberg’s term expires after 10 years at the helm of the Alliance.”After declaring his interest in the post last year, Mr Rutte gained early support from key members of the alliance including the United States, Britain, France and Germany.Others were more reticent, particularly Eastern European countries which argued the post should go to someone from their region for the first time.But they ultimately gave their support to Mr Rutte, who is a fierce critic of Russian President Vladimir Putin and a staunch ally of Ukraine.Outgoing Nato boss Mr Stoltenberg said he warmly welcomed the selection of Mr Rutte as his successor.”Mark is a true transatlanticist, a strong leader and a consensus-builder,” he said. “I know I am leaving Nato in good hands.”Nato takes its decisions by consensus, so Mr Rutte, who is bowing out of Dutch politics after nearly 14 years its Prime Minister, could only be confirmed once all 32 alliance members gave him their backing.Mr Rutte will face the challenge of sustaining Nato allies’ support for Ukraine’s fight against Russia’s full-scale invasion while guarding against Nato being drawn directly into a war with Moscow.He will also have to contend with the possibility that Nato-sceptic Donald Trump may return to the White House after the US presidential election on 5 November.Mr Trump’s possible return has unnerved Nato leaders as the Republican former president called into question the United States’ willingness to support other members of the alliance if they were attacked.