Many liberal philosophers claim that people are free to do as they will by default; any interference must be justified. This supposed presumption of liberty does a significant amount of theoretical work for public reason liberals such as Gerald Gaus and John Rawls. This paper shows that Gaus’s explicit defense of a presumption of liberty fails. Gausa and his many followers repeatedly appeal to a particular thought experiment from Stanley Benn. We argue that this thought experiment fails to show that (...) there is a presumption of liberty, but instead shows, at best, the trivial point that when any particular moral concern is specified to be the only relevant concern, then there is a presumption in favor of that concern. Further, Gaus, along with Shaun Nichols, has tried to demonstrate empirically that the intuitions and conclusions he draws from this example are fairly uniform and universal among other moral agents, but we explain why their experimental results do not vindicate any such conclusion. We conclude that undermining the alleged presumption of liberty places public reason liberalism in serious jeopardy. (shrink)