What if, following the fall of the Berlin Wall and the collpase of the USSR a few years later, capital-H History had kept on going, with various challenges and setbacks emerging against liberal democracy, rather than the relatively peaceful and prosperous march forward we've been experiencing since at least the late 1990s?
Who could some of the anti-liberal challengers could be. Radicalized Islam? A recalcitrantly authoritarian China? Environmental extremists, unimpressed with the pace and strength of the supposedly post-Historical international co-operation on the environment? Crazed economic populists in Europe and the American flyover?
Obviously in this scenario, the September 11th Statement On Global Co-operation And Priorities doesn't get signed, or is at least VERY different from what we got IOTL.