Arrival of vastly superior aliens would drastically change the context of all human existence. US standing as superpower, and the secondary and tertiary standing of all other nations, puts things in a completely different light. Presently the US is, within the real and profound limits of any power, the final word.
What would the existence of aliens do to religious belief. Or the idea that humans are special.
I'm sure that Europe and China would be purely delighted to hear that -not. America is not the pre-eminent power in the 21st Century. Mighty? Yes. Final word? No. But that's politics.
I think that - returning to the subject of first contact - aliens who are xenophobic, perhaps rabidly so, arn't going to bother doing a Hollywood Invasion. Why bother? Half a dozen Dinosaur Killers delivered from the edge of the system, at about 0.01c will do the job very nicely.