A Cook County judge is hearing arguments on whether to dismiss a case challenging Illinois' ban on same-sex marriage.
The lawsuit being heard Tuesday before Circuit Judge Sophia Hall involves 25 couples who filed for marriage licenses in Cook County and were denied.
However, Cook County State's Attorney Anita Alvarez has refused to defend the state's ban, which defines marriage as between a man and a woman. She says it violates the state constitution's equal protection clause. Attorney General Lisa Madigan has argued against the ban because the case brings the constitutionality of state laws into question.
Clerks from downstate were allowed to intervene and defend the ban.
Illinois approved civil unions in 2011, but attempts to legalize gay marriage have stalled.