> The US would still be required to abide by the Fourth Amendment though.
Only directly. The Five Eyes and other 'partners' routinely share intelligence with each other that their counterparts would face barriers to collecting.
I don't know what the likelihoods of either are but if I had to guess I would say that yes, hostile third countries are more dangerous than my own country.
Also, I consider that I would have more recourse against an actor from my own jurisdiction, I think you have pretty much zero recourse against the government of a hostile third country.
I don't trust even my own government. I'm not *more* worried about China messing with me. The NSA has more info on me that could potentially be used against me than Huawei. And I've never once seen a situation where the NSA digs data out of their vault to help exonerate an American on trial.