A Facebook logo. (Dado Ruvic/Reuters)

IN THE digital age, it is easy for everyone to make themselves heard on the Web — even terrorists. After a summer of high-profile attacks, the question for policymakers and the tech industry has been how to change that. A better question would be when and whether companies should be taking extremist content off the Internet at all.

At a forum this month on national security, Democratic presidential nominee Hillary Clinton doubled down on requests to social media companies to sanitize their sites of terrorist speech. “We need to work with Silicon Valley,” she said. “We . . . have to do a better job combating ISIS online, where they recruit, where they radicalize.” President Obama agrees. Propaganda, he has said, is too “pervasive and easily accessible.” It should be removed from the Web.

That’s not as simple as it sounds. Reuters reported that Facebook and Google were considering adopting an algorithm developed by the Counter Extremism Project that could instantly detect jihadist websites and posts. But it is impossible to say whether this or any technology could accurately answer difficult questions of speech.

The Internet can double as a breeding ground for radicalization, and sometimes, photos, videos and other posts actively incite violence. Yet there is a fine line between that material and content that is not only legitimate speech but also legitimate news: Citizens of every country deserve to know what is going on in the world and what people at both ends of the spectrum think about it — however hard that is to stomach.

Finding this line is not a job for an algorithm. Companies could use technology such as the Counter Extremism Project’s code to flag content and then put those posts in human hands. At that point, employees could determine what violates a site’s terms of service on their own, rather than trusting the string of letters and numbers the tool spits out. These employees should be as permissive as they possibly can without threatening anyone’s safety.

However social media companies decide to weigh the problem, the U.S. government would be wise to keep its finger off the scale. Technological tags help many other nations stamp out speech they don’t want to hear: China and Russia, for example, shut down dissent on the Web while claiming it is harmful to the country or citizens. That’s not a model the United States should legitimize. Instead, social media sites should tend their own gardens. They should also be wary as they weed them.