About $1 billion in anonymous contributions is coursing through midterm races across the country. Figuring out where the funds are coming from is no easy task.
Related stories
China threat bolsters support for EU industrial policy
Trump Tariffs Rattle Mainers as Susan Collins, Troy Jackson Face Tight Race
9/11 Responders' Trauma May Have Affected Their Children, Study Finds
Kallas pushes back on Franco-German reform plans for EU diplomatic service
Evander Kane Drama Explained as Hockey Player Shares Patrick Marleau Texts
Burnham pressed on economy at first PMQs as UK borrowing costs rise