George W. Bush has often expressed a belief that many Americans share: the United States is “the freest nation” in the world. But as a newcomer to the U.S. who has lived most of his life in other liberal democracies, it isn’t at all obvious to me that the United States is a freer nation than Australia, Canada, the United Kingdom, or the Netherlands, to give just a few possible rival candidates. Freedom can mean many things: that there is freedom of speech and thought, that people can associate with whomever they like and come and go as they please, that no one can be imprisoned without a fair trial, that each citizen has an equal voice in who governs them, that the government leaves people alone as long as they do not harm others, that people have the opportunity to realize their potential and prosper in the way they choose. These aspects of freedom are different in kind, and there is no single scale on which we can measure the extent to which one country is more free than another.
– Peter Singer in The President of Good and Evil (2004)