Four U.S. states recently took diametrically opposed approaches to address fundamental problems that their respective state legislatures identified in the online speech environment.  While controversial legislation in Florida and Texas sought to limit the ability of platforms to remove users or content, New York and California passed laws ultimately aimed at curbing hate speech and other forms of abuse on platforms.  In isolation, each of these legislative approaches raises significant First Amendment concerns, and all are likely insufficient to address the problems posed by online speech.  But what if the impetus behind these laws were combined into a unified regulatory approach?  Speech protection and speech limitation then might be better thought of as two sides of the same regulatory coin.

The role of speech on social media has gained increased attention in the wake of the January 6, 2021 attack on the Capitol.  Two themes emerged in connection with these events that unsettle long-standing constitutional assumptions in the United States.  First, the rigidity of the state action doctrine was gradually questioned in favor of users’ speech protection on private social media platforms against perceived censorship.  Second, the theme of “militant democracy” increasingly appeared as commentators asked whether democracy must offer its protections, including robust free speech, to those who actively seek to undermine it.

Both of these concepts, the horizontal effect of fundamental rights and militant democracy, are well established in other constitutional democracies, but in the past, they did not gain significant traction in the United States.  In comparative constitutional theory, militant democracy and the horizontal effect of fundamental rights tend to be studied in isolation but viewing them in tandem opens new perspectives.  This Article argues that one mechanism without the other is normatively undesirable, as is the absence of both.  But viewed together, they can be understood and operationalized as “democratic self-defense,” especially with respect to the vexing problems surrounding speech on social media platforms.