You've shifted your argument. Previously it was that you shouldn't vote because you didn't want to support democratic representatives who "don't have a backbone

You've shifted your argument. Previously it was that you shouldn't vote because you didn't want to support democratic representatives who "don't have a backbone", now it's that you don't want to vote because it doesn't matter. I'll also note that your vote for president has no impact on the senate's membership. It's entirely a non-sequitor.