You can still have meaningful elections when there’s only one party, people of the same party can run for the same position against each other, so there is still a choice between candidates. In fact, that’s how many places work in the US, in solidly red or solidly blue districts, generally all the serious candidates run in whichever party is essentially guaranteed to win in the general.
It’s true that in those situations the governing party can exercise control over who is allowed to run. But I don’t really see how that’s worse than the US system, where each party has complete control over the primary process and doesn’t even have to hold primaries at all if they don’t want to. Ultimately, I don’t see either system as particularly more democratic than the other.
If some entity can control who can and cannot be a politician, then the power is on the entity that control the politicians, not on the people.
For the people to have the power, they must be able to elect the leaders they want. If that leader has to be approved by an entity, the power is on that entity. That’s not a democracy, that’s a monarchy where the monarch makes opinion polls.
Then the US is a diarchy. The two parties have control of who can and cannot be in their party, and as you said yourself, the way the system is set up makes it virtually impossible to have more or fewer than two parties. The US is not a democracy because the people don’t get to choose their leaders, the leaders have to go through one of two entities and get approval there in order to have a chance to win.
As I said, the US is a flawed democracy (it’s not only my opinion, it’s ranked that why by global institutions). I’m not a US citizen btw. I’m a Spanish citizen, we have better democracy over here.
Even though the US is flawed, having 2 parties is massively more democratic than having 1. Because with 2, you at least have the “party in power” and “the opposition”.
I’ll tell you a bit about Spanish history while we’re at it.
Since a bit before WWII, we had a dictatorship, with a single party. Then the dictator died at old age of natural causes and his successor was blown up by a terrorist organization. So we got democracy. At first there were only 2 parties, not because the system made it so (like in the US), but because voters voted that way. Then, people got fed up of having 2 options and were unhappy, so they started to vote for smaller parties and now we have many of them.
If people are so unhappy with having 2 options that they change their voting pattern that they’ve held for 40+ years, imagine how bad it is to have 1 single party.