Well before John Stuart Mill, Spinoza had the acuity to recognize that the unfettered freedom of expression is in the state’s own best interest. In this post-9/11 world, there is a temptation to believe that “homeland security” is better secured by the suppression of certain liberties than their free exercise. This includes a tendency by justices to interpret existing laws in restrictive ways and efforts by lawmakers to create new limitations, as well as a willingness among the populace, “for the sake of peace and security,” to acquiesce in this. We seem ready not only to engage in a higher degree of self-censorship, but also to accept a loosening of legal protections against prior restraint (whether in print publications or the dissemination of information via the Internet), unwarranted surveillance, unreasonable search and seizure, and other intrusive measures. Spinoza, long ago, recognized the danger in such thinking, both for individuals and for the polity at large. He saw that there was no need to make a trade-off between political and social well-being and the freedom of expression; on the contrary, the former depends on the latter.