Maryland Gov. Martin O’Malley (D) on Thursday night predicted that an expected referendum on same-sex marriage would pass in November but said that a loss would not set back the larger cause of gay rights.

Gov. Martin O'Malley, center, signed the Civil Marriage Protection Act in Annapolis, Md., on March 1. (AP Photo/Patrick Semansky)

Opponents of the same-sex marriage bill that O’Malley signed last week have vowed to gather enough signatures to force a public vote on the issue in November.

O’Malley acknowledged the “likelihood” that the measure will be on the statewide ballot. He told Maddow that he thinks the new law will survive because many of the same kind of conversations about “human dignity” that took place among legislators will play out among voters.

“I think that’s what people are going to do now as they talk around their own kitchen tables, in their family living rooms and at work,” O’Malley said.

Asked by Maddow about the implications of a referendum that fails, O’Malley suggested it would not hurt the “march of progress” on the issue.

“The march of human understanding, of mutual respect for one another cannot be turned back,” O’Malley said.