A gay couple from Montclair, N.J., whose engagement photo was used in Colorado political attack mailers are "innocent bystanders" whose image was stolen, and their lawsuit against the group who used it should proceed, attorneys said in a court filing.

"They are not celebrities or public figures or emblems of the gay-rights movement. They did not insert themselves into Colorado politics," attorneys with the southern Poverty Law Center said in a filing in Denver federal court Monday on behalf of Brian Edwards, 32, and Tom Privitere, 37.

The filing was in response to arguments by a group named Public Advocate of the United States, which said last month that the suit should be dismissed.

The Virginia group, which lobbies for issues such as traditional marriage, said that by using the photo in the mailers it was "engaging in the type of political speech" protected by the First Amendment.

"Whether one agrees with Public Advocate's position or even finds it hurtful, repulsive, and beyond the bounds of decency is utterly beside the point," attorneys for the group argue in a filing last month.

A hearing on Public Advocate's motion to dismiss the case has not been set. The suit was filed in September.

The group took a photo that Edwards and Privitere posted on their blog showing them holding hands and kissing with the Manhattan skyline in the background. The image was used without their permission in mailers in a June primary election involving State Sen. Jean White, one of a handful of Republicans who supported a civil unions bill then blocked in the state House.

The mailer, which replaced the Manhattan skyline with a snowy background, read: "State Senator Jean White's Idea of 'Family Values'?" White lost the primary.

Public Advocate also used the couple's photo in a mailer for another Colorado state legislative race.

Attorneys for Edwards and Privitere argue that "there is no independent First Amendment defense to copyright infringement."