Last fall, a court filing in the Eastern District of Virginia inadvertently suggested that the Justice Department had indicted WikiLeaks founder Julian Assange. The Wall Street Journal, the New York Times, and other outlets reported soon after that Assange had likely been secretly indicted for conspiring with his sources to publish classified government material and hacked documents belonging to the Democratic National Committee, among other things.

Illustration by Ricardo Martínez

As a veteran of major free-press legal battles, I waited, throughout the days that followed, for journalists to come to Assange’s defense. A few reliable advocates, such…