Liz Garbus’s subject is free speech and why it is the basis of a free society. Garbus’s storytelling genius is in her use of the loveable, common-sense persona of her father, Martin Garbus, a famous First Amendment attorney. We are held rapt by several legal cases: a professor’s outspokenness after 9/11 that led to his firing from the University of Colorado, the principal of a public school in New York being caught up in irrational anti-Muslim frenzy, and the Poway, California, high school student’s handmade anti-gay T-shirt. How free is free speech?Garbus brings up cogent examples from past interpretation and defense of the First Amendment, such as the scare of McCarthyism, the publication of the Pentagon Papers, and the Skokie, Illinois, march by neo-Nazis. This film demonstrates the best of documentary filmmaking by being reflective and consistently probing, with abundant narrative drive.