Gay GOP group GOProud has endorsed Carly Fiorina, an opponent of gay marriage, over moderate Republican Tom Campbell, who supports the institution, in the fight to oust Senator Barbara Boxer, a three-term Democrat from California.

“Carly Fiorina is the candidate conservatives can trust,” Jimmy LaSalvia, executive director of GOProud, said in his endorsement.

The group has been critical of Campbell, a former congressman. In a 30-second web ad released in April, the group attacked Campbell for “increasing taxes on California families.”

The group says it favors Fiorina despite her public opposition to gay marriage because she has pledged not to raise taxes. Campbell has refused to sign the Taxpayer Protection Pledge, explaining that “you don't know what the future is going to be.”

In supporting Fiorina, GOProud finds itself in agreement with an unlikely ally: The National Organization for Marriage (NOM), the nation's most vociferous opponent of gay marriage. The group is spending $300,000 in the state on ads attacking Campbell for his support of gay marriage. NOM says it can wrench primary votes away from Campbell because the majority of Republicans are unaware that he supports gay marriage.

This is NOM's first major outing in California since it led the effort to pass Proposition 8 – California's gay marriage ban – in November of 2008.

In an email to On Top Magazine, LaSalvia explained that Campbell must be judged on national issues, not state issues such as California's gay marriage ban.

“Prop 8 was and is a state issue and we agree strongly with Rep. Campbell on Prop 8,” LaSalvia said earlier this year. “However, the totality of his record on issues of importance to gay conservatives – particularly his record on taxes and foreign policy – is abysmal.”

While polling suggests Campbell would make a stronger opponent to Boxer in the fall, former Hewlett-Packard CEO Fiorina currently leads in the contest to win the Republican nomination. In March, Campbell held a narrow lead.

“We expect her to continue her momentum and win the GOP nomination,” LaSalvia added.

Senator Boxer, a Democrat, supports giving gay and lesbian couples the right to marry. Fiorina says she supports California's domestic partnership law but believes in the “sanctity of marriage between a man and a woman.”