A third of Americans have fallen for Russian disinformation as well as other false online claims about health, elections and international conflict.
Republicans were, though, more likely to believe Russian disinformation claims than their Democratic counterparts, with 57.6% falling for at least one Russian disinformation claim, compared with just 17.9% of Democrats and 29.5% of people who didn't identify with one particular party.
But it's amplified in countries with undemocratic election systems, like first past the post. You just need a plurality of morons to fuck it up for everybody else.
To be honest, this is not directly caused by the US. Reason for this is propaganda/misinformation by states like Russia and China and (a)social media like Twitter, Facebook, TikTok,...