At 2:30 p.m. on Thursday, Representative Maxine Waters was on the floor of the House of Representatives, arguing for the importance of the Securities and Exchange Commission.

“At this time,” Ms. Waters, Democrat of California, said, “with a bill that would basically take our cop on the block, the S.E.C., and literally obliterate ——”

Alas, politics junkies, news editors and anyone else who was watching the broadcast online did not learn how that sentence ended. Ms. Waters was cut off. Instead, they heard the jangling music of a feed from RT, a state-run Russian television network that has been accused of helping its government interfere in the American election.

Some on social media immediately assumed that the interruption, which lasted about 10 minutes, had nefarious implications.