I grew up in McHenry IL. Illinois has been extremely liberal over the years. It was one of the first states to revoke the ban on interracial marriages. Note that only certain towns and counties had this ban {mostly in the southern part}, not the whole state. The state made a blanket removal of the ban across the state. It was one of the first to revoke ban on sodomy. Chicago was one of the first to offer benefits to same sex partners of city employees.

I don't think Schwarzenegger personally cares whether or not same-sex marriage is legal in California. His chief of staff is a lesbian, and he equivocated earlier this year about whether he woud sign a same-sex marriage bill if it passed in the CA legislature. The Calif. legislature did pass a bill legalizing same-sex marriage in 2005 (the only state legislature to do so) but Schwarzenegger vetoed it – almost certainly for political reasons. He didn't want to be embroiled in the referendum that would be sure to follow.