C-SPAN's "Washington Journal," a political institution featuring callers questioning and opining on prominent guests, is now incorporating Twitter into its longstanding format.

Twitter users can now follow the program at http://twitter.com/cspanwj, and, maybe more importantly, tweet their questions for guests.

Twitter joins phone, fax, and email as the latest medium through which viewers can pose their questions or comments on the program, which has been on-air since 1980.

Watch some videos of C-SPAN guests responding to tweets -- including the first time "Washington Journal" used Twitter -- after the jump.