I'm not so sure. I see no reason to accept the liberal pretension that history is linear and closed. I'm not even sure what it means for history to end. Does that mean Western liberalism is the outcome of history? That would make prior imperialists blush. As for the US, it dominates by other means. It's also rather difficult to explain our global military presence and our frequent aggression (regardless of how it's justified...justification does not make us unique) outside the concept of empire.