American voters deliver their verdict on Tuesday after an extraordinarily turbulent election that will either make Kamala Harris the first woman president in US history or deliver Donald Trump a comeback that sends shockwaves around the world. As polling stations open nationwide on Election Day, Democratic vice president Harris, 60, and Republican former president Trump, 78, are dead-even in the tightest and most volatile White House race of modern times. The bitter rivals spent their final day of the campaign frenziedly working to get their supporters out to the polls and trying to win over any last undecided voters in the swing states expected to decide the outcome. But despite a series of head-spinning twists in an unprecedented campaign — from Harris’s dramatic entrance when President Joe Biden dropped out in July, to Trump riding out two assassination attempts and a criminal conviction — nothing has broken the deadlock in the opinion polls.