Rick Santorum on Monday accused GOP presidential rival Mitt Romney of being more liberal on gay marriage than President Barack Obama.

Santorum, a former senator from Pennsylvania, made his remarks during an interview on Laura Ingraham's radio show.

When Ingraham asked Romney's stance on a proposed bill that would repeal the Defense of Marriage Act (DOMA), Santorum answered: “I would argue that Mitt Romney, as governor of Massachusetts, was to the left of Barack Obama on the issue of gay marriage.”

DOMA is the 1996 law that bars federal agencies and the military from recognizing the legal marriages of gay and lesbian couples.

“If you want to see the contrast, the contrast is there. [I'm a] solid conservative who fought for the federal marriage amendment as opposed to Mitt Romney, who issued gay marriage licenses and actually violated the constitution of Massachusetts to institute gay marriage in his state,” he said.

“One of the reasons I do talk about the past is because I have the best record in the field,” he added. (The audio is embedded in right panel of this page.)

As governor of the first state to legalize gay marriage in 2004, Romney granted special waivers that allowed a non-clergy individual to solemnize a marriage. The One Day Marriage Designation is not a marriage license. However, applicants must include the name, address and date of birth of the couple he/she wishes to marry.