Deep fakes—highly realistic and difficult-to-detect depictions of real people doing or saying things they never said or did—are a profoundly serious problem for democratic governments and the world order. A combination of technology, education, and public policy can reduce their effectiveness.

The United States defined its preferred cyberspace norms—Internet openness, security, liberty, free speech, and with minimal government oversight and surveillance—in its 2011 International Strategy f…