The United States is a republic, not a democracy.
People say that like it’s the most insightful thing ever, but it’s meaningless. It’s like saying your dog is an animal, not a pet.
These things are not opposites, nor are they mutually exclusive.
If you want to say “a republic, not a direct democracy,” you might be onto something at least factual. But you know exactly why the people who love to say this don’t use the qualifier: it’s a sophomoric debating trick to deflect any legitimate criticism of our system as being undemocratic.
Us: “Voter purges are undemocratic!” Them: “It’s a republic, not a democracy!” Er, that’s not on point but it sounds cool if you’re gullible.
Beau explains this in a better way and more completely than I can: https://www.youtube.com/watch?v=qYScSvpqZXU