A common objection to political liberalism is that since reasonable citizens agree that some ways of life are worse than others – for instance that the life of a drug addict is less worthwhile than the life of a person who spends her time with family and philosophy – political liberals must concede that the state can sometimes permissibly use perfectionist reasons. I argue in this paper that this challenge is mistaken, because the comparison only tells us something about relative, (...) not absolute, value. And because the real question concerns what the right justificatory constituency looks like, not what counts as reasonable in some other sense, the implication is that perfectionists and political liberals could construct equally plausible idealised constituencies. This stalemate gives us reason to develop arguments in favour of our preferred justificatory constituency. We cannot view local comparative judgements in isolation. (shrink)