In a legal brief filed Monday defending his decision to issue marriage licenses to gay and lesbian couples in defiance of Pennsylvania law, D. Bruce Hanes, register of wills for Montgomery County, called the marriage ban “arbitrary and suspect.”

Hanes' office has issued roughly 135 marriage licenses to gay couples in the last month. More than a third of the couples have married.

(Related: Mayor John Fetterman performs first gay wedding in Allegheny County, Pennsylvania.)

According to the AP, Hanes, a Democrat, cites in his filing the recent Supreme Court ruling that struck down Section 3 of the Defense of Marriage Act (DOMA), which prohibited federal agencies from recognizing the legal marriages of gay and lesbian couples.

In the brief, filed by the Montgomery County Solicitor's Office, Hanes said: “Pennsylvania's DOMA statute is arbitrary and suspect, and is very similar to the statute which was struck down [by the Supreme Court].”

The administration of Republican Governor Tom Corbett sued Hanes to stop him from issuing additional licenses to same-sex couples.

Hanes announced he would begin issuing the licenses soon after Attorney General Kathleen Kane, a Democrat, refused to defend the law in a separate legal challenge.

(Related: Rep. Daryl Metcalfe: Impeach officials who issue gay marriage licenses.)