<< They're not acting like they're trying to build power, it's something else. Even Trump's bluster is not really building power in any way, it's only undermining American hegemony at a staggering rate.

That is arguable, but let us assume it is true for the sake of the argument. If that is true, would you agree that US hegemony seriously waned over the course of at least 4 administrations before Trump?