The State Central Committee of an established political party is authorized by that part of the Illinois statutes known as the Election Code.  Section 7-7 of the Code says the Committee's "responsibilities include, but are not limited to, filling by appointment vacancies in nomination for statewide offices, including but not limited to the office of United States Senator."  The ILGP, at its October 2007 Membership Meeting, opted for "Alternative B" as described in Section 7-8 of the Election Code, whereby the Committee is formed of one male and one female committeeperson from each of the state's 19 congressional districts, eventually to be elected from the districts in non-presidential even-numbered years (starting in 2010).  The first 15 members of of the Committee were appointed in 2007 by the Party's highest vote-getting candidate in the 2006 election (Rich Whitney), in accordance with the power granted to him by Section 10-2 of the Election Code to set up a "provisional party organization".
    Vacancies on the State Central Committee can be filled, according to Section 7-8 of the Election Code, "... by appointment of the chairmen of the county central committees ... of the counties located within the congressional district in which the vacancy occurs...", with additional conditions for counties of over 2 million population (namely Cook).