> the US has always been an expansionist and later empire-seeking country at least for significant (i.e. with enough influence) parts of the powerful.

That’s not true at all, at least not in historical context. The US is the most powerful country in the world never to build an actual empire. It’s conquests are limited to part of Mexico, and some pacific islands. It’s predecessor, Great Britain, colonized India, Africa, Oceania, and the Americas, and turned China into a vassal state. The would-be challenger Germany occupied France, Belgium, the Netherlands, Poland, etc.

The US is interventionist—it intervenes in the political affairs of other countries to perpetuate the status quo. That’s very different from being expansionist or Empire-seeking. Take Iraq for example. The US toppled the government. But did it colonize the country? Annex the oil fields? Turn the oil over to domestic oil companies like Exxon? No. (Most of the development rights went to BP, a British company!) The US spent far more on Iraq then it got out of the country. That’s not how an Empire operates.