No, but I’m a registered Democrat. I’ve lived in several states, and not all of them allow you to vote in their primaries of you’re not a registered member. So the Democrat party is my party.

Now, if we ever get rid of the electoral college, and replace FPtP with approval out ranked-choice voting (or, almost literally anything else besides FPtP), that’ll change. But for now, I accept the reality that we vote for the lesser of two evils, or we throw away our vote in a futile, and unnoticed, gesture.

You can be a member of a party without being a politician. As far as I understand it (I could be wrong, not American), the process for signing up in the US is a state-by-state thing, not at the federal level.