WASHINGTON--Sen. Mark Kirk (R-Ill.) will endorse GOP presidential candidate Mitt Romney in Chicago on Monday morning, a move that had been expected. Kirk will be joined at a Loop press conference with Illinois State Treasurer Dan Rutherford, who has been organizing Illinois for Romney.

Romney has the deepest Illinois operation of any of the 2012 Republican rivals. People have already been recruited to run for delegates and major Illinois endorsements have been out for months. In backing Romney, Kirk follows a string of Illinois Republicans: former House Speaker J. Dennis Hastert, Rep. Judy Biggert and Rep. Aaron Schock.

Newt Gingrich is just starting to get an Illinois organization. Delegate slates are due next month for the March Illinois primary. Crain's Chicago Business Greg Hinz is reporting that Gingrich has has conversations with state Sen. Bill Brady.