Chicago, IL — The Thomas More Society, a conservative nonprofit legal group, filed a motion late Friday to intervene in the same-sex marriage lawsuit filed by the ACLU and Lambda Legal.

The motion to intervene was filed on behalf of Effingham County Clerk Kerry Hirtzel and Tazewell County Clerk Christie Webb and seeks the right to defend the current law banning gay marriage.

The request by the Society to enter the case follows the decision of Cook County State's Attorney Anita Alvarez and Illinois Attorney General Lisa Madigan not to defend the state's ban on same-sex marriage. Alvarez and Madigan agree with the 25 gay and lesbian couples who claim in the lawsuit that the ban is unconstitutional.

Cook County Clerk David Orr, who is the subject of the original suits, agrees that the current law is unconstitutional and refuses to defend it.

"Despite a statewide campaign by homophobic groups trying to convince county clerks to defend the current marriage law, only two of the 102 clerks stood up for perpetuating discrimination," said Randy Hannig, Director of Public Policy for Equality Illinois.

An Equality Illinois study released in June found clear and consistent patterns where civil union couples were treated unequally, denied rights or protections, or stigmatized.

"As we feared, civil unions did not turn out to be equal to civil marriages, and separate does not make equal," said Bernard Cherkasov, CEO of Equality Illinois. "Sadly, our research also found that in area after area, whether tax law, health insurance, hospitalization, family issues, personal finance and actions by state and local officials, couples in civil unions were either treated unequally or denied their rights, or singled out for discrimination."

The intervention motion is set for hearing on Tuesday, July 3.