Lots of questions about how Obama's seat gets filled now that Gov. Blagojevich is under arrest, charged with conspiring to solicit bribes in return for appointment to the seat.

The Illinois attorney general's office tells us they're researching the question now. Meanwhile, Sen. Dick Durbin (D-IL) is calling on the Illinois legislature to immediately call a special election for the seat to deprive Blagojevich of the power to name Obama's successor.

Late Update: Here's Durbin at his press conference today on the Hill: