Minority rule is guaranteed by the constitution because of the senate. All the GOP has to do is push right when they have the presidency, which assures them the senate and house for at least two years too, and then hold the line using the filibuster any other time. They don't care what the people want, they're not put in power by the people but by the map.
Having control of the Senate (within 20 years 2/3 of which will be elected by less than 1/3 of the population) means they get to gate-keep appointments to the Supreme Court, which in turn can block any attempt to fix the Senate or any other aspect of the oligarchic US system. Then there's the electoral college, and the gerrymandering at the State level.
It's a beautiful system, if your aim is to ensure the rule of a privileged minority in perpetuity. I think that was the whole purpose of it from the start.
Over here, I'm quite nervous what will happen when the pretentious nincompoop Charles becomes monarch. Given his bottomless self-regard and lack of inhibitions about exploiting his unelected power, he could well reveal the fundamental weaknesses of our system in much the same way.
Just as the weaknesses in the US system were concealed for a long time by the relatively moral nature of the accidental incumbents in the Supreme Court, we've been lulled into complacency by the (relative) good sense of our Lizzie.