There's argument to be made we didn't have a functioning democracy when the Constitution was ratified in 1789, since segments of it were clearly written in bad faith (like the electoral college, the 3/5s of all non-free persons clause, and arguably, the failure to offer suffrage to all persons including women), but Boss Tweed in 1852 already understood how to game the elections so that only approved candidates might make it to primaries (of New York State elections and Federal elections).

In the aughts (the 2000s), Oxford University did a study regarding elections, public interests and elite interests, and determined the US behaved more like an oligarchy than a democratic republic, so yeah, we're a plutocracy with some democratic features. However those democratic features, while meager, keep the US from turning into a single-party autocracy like the German Reich or the late-stage USSR.

And we're moving towards that autocracy, propped up by fascist ideology (with enemy within rhetoric, and purge actions to follow) with every year. The next time the Republican takes control of all three federal branches of government, the game is very likely up.

The US is also on the brink of civil war, and it may be sparked by Trump losing, depending on how large and coordinated the coup d'etat effort is at the time, or if Trump wins, by an attack against those resisting draconian policies.