Religious liberty enjoys a large measure of protection in liberal democratic states. This historically hard-won right will nevertheless always remain somewhat vulnerable. This article examines the relationship between liberalism and religionists who challenge key liberal tenets. The limits of liberal tolerance are seen when the state confronts those devout believers who behave or speak in the public domain in a manner that secular liberals perceive to be intolerant or bigoted. The courts and legislatures cannot be relied upon to protect the exercise of religion in situations where fundamental liberal premises are at stake.