It's completely ok to spend citizens' money on benefits both old and new, if that's what society decides. It might not always be smart, or sustainable. Just as

It's completely ok to spend citizens' money on benefits both old and new, if that's what society decides. It might not always be smart, or sustainable. Just as it wouldn't be smart not to do it at all. But there's no first principle of morality to reduce to. And if there were, there'd be you'd still need agreement on it for it to be meaningful.