The National Organization for Marriage (NOM) will once again ask presidential candidates to sign a pledge to work against marriage equality, but this time the group is limiting its request to Republicans.

“Republicans need to not just give lip service to marriage,” NOM President Brian Brown told CNN. “By signing the pledge they are committing to concrete steps to protect marriage.”

NOM's key demands remain a promise to support a federal constitutional amendment limiting marriage to heterosexual unions and the investigation, documentation and promotion of the harassment of marriage equality opponents by federal officials.

New this year is a pledge to “oppose and work to overturn any Supreme Court decision that illegitimately finds a constitutional 'right' to the redefinition of marriage.”

Dropped from this year's pledge are promises to defend the Defense of Marriage Act (DOMA) in court and back legislation that would allow a ballot question on the issue for voters of the District of Columbia.

“Our hope is that as many candidates as possible sign,” said Brown, “but at the end of the day what we want is a champion for marriage, someone who will stand up and do what is necessary to protect it. So whether we end up having four candidates or 15 we are going to support the candidates that stand up and sign the pledge.”