Not voting probably doesn't achieve much, but it does at least reduce the turnout. It's possible that a low turnout may encourage a new modern party to spot an opportunity to inspire the non-voters into voting for them.
But really the smart way to not vote is to at least turn up, and write your thoughts all over the ballot paper. Then it's a spoiled ballot paper, which does get counted, and read out, and at least lets those in power know that you can be arsed to turn up but hate the lot of them. This really could inspire them to offer something different.
But voting for someone other than the terrible two is probably the best protest. It doesn't matter who, just whoever bothers running where you live. There's a risk of this backfiring, e.g. splitting the vote of the least terrible one so that the really awful one wins instead, but the system's too knackered to bother caring any more. Besides, I really don't know which of the two is the least terrible any more, if one of them is going to win then I don't care which it is. If whatever protest party I vote for actually wins then it's probably not going to be any worse anyway, so there's no risk.
But really the smart way to not vote is to at least turn up, and write your thoughts all over the ballot paper. Then it's a spoiled ballot paper, which does get counted, and read out, and at least lets those in power know that you can be arsed to turn up but hate the lot of them. This really could inspire them to offer something different.
But voting for someone other than the terrible two is probably the best protest. It doesn't matter who, just whoever bothers running where you live. There's a risk of this backfiring, e.g. splitting the vote of the least terrible one so that the really awful one wins instead, but the system's too knackered to bother caring any more. Besides, I really don't know which of the two is the least terrible any more, if one of them is going to win then I don't care which it is. If whatever protest party I vote for actually wins then it's probably not going to be any worse anyway, so there's no risk.