The economic consequences of WW I & II catapulted the US (and Canada proportionately) by all measures of geopolitical power and significance ahead of its rivals at an unsustainable speed and to an extent.

The US (and Canada) are now not destined to languish and wither. However, other regions and nations, no longer impeded by the dislocations and destruction of those wars or the impact of colonialism, are regaining strength and influence proportionate to their size and state of economic, social and political development.  North America can continue to do well but, we have lost our artificial advantage in some fields.

Having been undisputed number one for over three decades since WW II, the US and especially American engaged in the fields under renewed comptition are having difficulty coming to terms with the end of their post-WW II Golden Age.

Trumpism is the last gasp, reactionary attempt to deny this reality.  It too will pass.