If democracy is rule by the people, and populism appeals to the people for legitimacy,

how can we distinguish a populist movement from one seeking to establish a liberal

democracy? Existing conceptions of populism in political science can distinguish the two

within stable electoral systems; but they cannot do so during constitutional crises. This

paper offers a new lens for examining populism in crisis situations. By examining recent

debates on the nature and composition of the people, the paper proposes a different

criterion of demarcation between populism and liberal democracy: self-limitation.

Populists, I argue, defend their policies by claiming that the people wants them. By

contrast, liberal democrats also appeal to the people, but only to signal that their claims

are fallible, and thus to limit the reach of their claims. The paper illustrates the thesis by

applying the criterion to the contested 2006 elections in Mexico.