Mark Zuckerberg’s testimony before the Senate Judiciary and Commerce Committees last week had some strange scenes. One minute he’s describing Internet service providers as “pipes,” the next he’s asked to identify potential Russian Facebook groups on a piece of poster board.

The hearing was ostensibly about data privacy, but that subject (and the hearing’s more outlandish moments) are not the only reason Americans should care about Facebook. Zuckerberg’s exchanges with senators have important implications for political speech rights as well.