So what is an oligarchy?
an oligarchy is a form of government where the rich do the thinking, the government control - but it isn’t just solely the rich so think of royalty, militia, etc. those fit the theme of someone who is “important”
Now the American government is a democracy - meaning the people vote for whom is in office, because it’s representative of them (the people) however the people we see as senates, presidents, and other forms of being a politician; they are fairly wealthy either from their backgrounds (family wealth) or because they’re a politician (it takes a lot of money to be one)
I think it’s an oligarchy but with extra steps. Like in England you have a monarchy - direct oligarchy while America is an oligarchy with extra steps. So yes and no - by definition of governments no, but by how it actually runs? Yes.
I hope this helps - I know it said ASAP so I might be too late :(