A U.S. District Court judge in Colorado has issued a split decision in the federal case of a same-sex couple who alleged that Loudoun County Supervisor Eugene A. Delgaudio’s conservative advocacy group illegally used the couple’s private engagement photo on anti-gay-marriage campaign fliers in Colorado.

Senior U.S. District Judge Wiley Y. Daniel found that the plaintiffs — New Jersey couple Tom Privitere and Brian Edwards, and photographer Kristina Hill, who took the original image — have a “plausible copyright infringement claim” but dismissed their allegation that the couple’s likenesses had been illegally misappropriated.

The Southern Poverty Law Center, a prominent civil rights organization, filed the complaint against Delgaudio’s conservative advocacy group, Public Advocate of the United States, in September 2012, after the photo of Privitere and Edwards was used by the organization on campaign mailers that attacked a Colorado lawmaker for supporting same-sex civil unions. The Southern Poverty Law Center later added two Colorado-based pro-gun rights groups to the lawsuit after they were linked to the production of the campaign fliers.

The original photo, taken by Hill in 2010 and originally posted on Edwards and Privitere’s wedding blog, shows the couple kissing in front of the New York skyline. In one of two altered images used on the campaign flier widely distributed by Public Advocate, the urban backdrop was replaced by a snowy country scene, and a bold red banner emblazoned with the words “State Senator Jean White’s Idea of Family Values?” cut across the couple’s chests.

The plaintiff’s lawsuit alleged that Public Advocate’s use of the image violated federal copyright law and also constituted unlawful misappropriation of the couple’s likenesses.

Public Advocate sought dismissal of the lawsuit on the grounds that the use of the photo was fair and protected by the First Amendment.

Daniel agreed, saying in his March 31 order that the claim of misappropriation would be dismissed because the First Amendment allows for the use of an image that pertains to a matter of public concern.

“The test of whether the First Amendment privilege applies is whether a defendant’s use of a plaintiff’s name or likeness reasonably relates to a publication concerning a matter that is newsworthy or of legitimate public concern,” the judge’s order said, adding that the use of the photo in the mailers “reasonably relates to a matter of legitimate public concern: same-sex marriage.”

But the plaintiffs’ copyright infringement claim should proceed, the judge ruled.

In a statement April 1, Delgaudio (R-Sterling) hailed the court’s ruling as a “tremendous victory” for Public Advocate.

“We continue to believe we have the right to defend traditional marriage and will redouble our efforts to oppose homosexual marriage,” he said. He said his group would continue to seek donations from supporters as the copyright case proceeds.

Anjali Nair, a Southern Poverty Law Center staff attorney, had a mixed reaction to the ruling.

“We are happy that the court has ruled that the defendants’ unauthorized use of the engagement photo may violate the copyright laws and that the copyright claim may proceed to trial,” Nair said in an e-mail. “We are disappointed with the court’s legal ruling on the misappropriation claim and remain convinced that the misuse of our clients’ private engagement photo was wrong.”

Delgaudio’s Falls Church-based organization, which was designated a hate group by the Southern Poverty Law Center in 2012 — a label Delgaudio is fighting — has drawn widespread attention for its anti-gay messages in recent years. Delgaudio has cited airport pat-down security procedures, anti-bullying legislation and a Florida pirate festival as evidence of what he calls the proliferation of “radical homosexuality” in the United States.

The four-term supervisor is also defending himself against a recall petition filed by Sterling voters who seek to remove him from his seat on the county Board of Supervisors, citing allegations that he used his public office to benefit his political campaign. That case is pending in Loudoun County Circuit Court, with a hearing set for May 6.