Cook County State's Attorney says gay marriage ban violates Illinois state constitution

The Illinois attorney's office has announced that it will concede that the state's ban on marriages for same-sex couples is unconstitutional in conjunction with two lawsuits filed against the Cook County Clerk.

The governor, the Attorney General, and now the state attorney of Cook County all support same-sex marriage in Illinois.

Cook County State’s Attorney Anita Alvarez’s office says she’ll submit a filing Thursday that indicates she agrees with several parts of two lawsuits challenging the same sex marriage ban in Illinois, in a move that signals another legal victory for proponents of same-sex marriage. Alvarez's office said it "will admit the salient allegations within the complaint and concede that the equal protection clause of the Illinois Constitution prohibits discrimination in the issuance of marriage licenses based upon sex or sexual orientation." "We are in agreement with the plaintiffs that Illinois laws that prohibit same sex marriage are unconstitutional. We believe the plaintiffs are correct in their assertion that the Illinois Constitution upholds marriage equality for same sex couples just as it does for opposite sex couples," the statement said.

I'm certain anti-gay groups will step forward to defend against the suit themselves.
Same-sex couples in Illinois are currently able to enter into civil unions.