Turning 75 this year, NATO faces an old foe and new squabbles. Created at dawn of the Cold War by the US and 11 allies, it now strains to unify 32 members. The diversity of views that expansion brought has complicated many decisions and the Alliance’s future is under scrutiny, widening a geopolitical rift that emerged with Russia’s invasion of Ukraine, China’s challenge and the unending crisis in the Middle East .