The legitimacy claims of liberal democratic states are typically couched in thelanguage of individual rights and the rule of law. But contemporary liberaldemocratic states increasingly appeal to a logic of security, law and order, andthe need to combat “political extremism.” This logic playsout in Ukraine, Egypt, and Turkey, and in Greece and Germany, but also in theU.S., France, and the UK. It is an increasingly important feature of politics insocieties that may be experiencing a rough “transition todemocracy,” but also in societies that are conventionally regarded as“consolidated democracies.” The normative and practicalchallenges presented by this situation are fundamental. Alexander S.Kirschner’s A Theory of Militant Democracy: The Ethics of CombattingPolitical Extremism offers one interesting take on these issues, which cut tothe core of political science as a discipline. We have thus invited a range ofpolitical scientists from a variety of subfield and methodological perspectivesto comment on the book and on the broader topic the book engages—theethics of combatting political extremism and indeed the very politicalconstruction of “political extremism.” -- Jeffrey C.Isaac