The NATO summit in Turkey got off to a rocky start, with US President Donald Trump slamming Spain for failing to spend on defense and other alliance members for refusing to pitch in during the Iran war. But by the end of the day, unity was the key word from leaders, including the US president.

As Trump arrives in Ankara, Nato faces a defining test over America's role, Europe's new responsibilities and Turkey's defence industry ambitions

As NATO leaders gather in Ankara tomorrow, Tuesday, the alliance faces a stark test of unity, burden-sharing and strategic clarity, with the war in Ukraine, transatlantic tensions…