 Three gruelling days and a world stage for the US president to prove he's still up to the job. The summit marks the 75th anniversary of NATO and there are weighty issues to consider. Russia's war in Ukraine, perceived threats posed by China and security in the Indo-Pacific region. Joe Biden is used to the pressures, the back-to-back meetings, speeches and dinners that come with an international gathering like this. But his ability to navigate the week will be scrutinised constantly.