The North Carolina chapter of the National Association for the Advancement of Colored People (NAACP) has joined the fight against a proposed constitutional amendment that would ban gay marriage in the state.

Lawmakers will begin debate Monday on whether to send the proposed amendment to voters next year.

North Carolina NAACP President Rev. Dr. William Barber denounced the measure in an open letter to lawmakers released on Friday.

“The NAACP does not and has not taken a position endorsing or opposing gay marriage,” wrote Barber. “However, the NAACP has a long history of opposing any proposal that would alter the federal or state constitutions for the purpose of excluding any group or individuals from guarantees of equal protection under the law. Our opposition is based on our mission statement, which calls for the 'equality of rights of all persons.'”

“A vote on the same-sex marriage amendment has nothing to do with your personal opinion on same-sex marriage but everything to do with whether or not you believe discrimination should be codified and legalized constitutionally.”

“The NAACP strongly urges you to reject the so-called same-sex amendment and any other present or future proposals of constitutional amendments that would permanently deprive any person in our great state of his or her inalienable rights,” Barber concluded.

The action comes less than a week after the Maryland chapter of the NAACP joined the effort to legalize gay marriage in Maryland.