"The Biden administration," CNN reports, "is considering using outside firms to track extremist chatter by Americans online."

Federal law enforcement agencies are legally and constitutionally forbidden to monitor the private activities of citizens without first getting warrants based on probable cause to believe those citizens have committed, or are committing, crimes. The feds can browse public social media posts and so forth, but secretly trawling private groups and hacking encrypted chats is off-limits.

Private companies and nonprofit civic organizations, not being government entities, d...