WASHINGTON — (CNN) Candidates seeking the Republican presidential nomination will be urged Thursday to sign a pledge promising to support a constitutional amendment defining marriage as being between one man and one woman.

The National Organization for Marriage’s request comes as the nation waits to see if the U.S. Supreme Court will rule this month to legalize same sex marriage across the country.

“Republicans need to not just give lip service to marriage,” Brian Brown, president of the organization, told CNN in an interview. “By signing the pledge they are committing to concrete steps to protect marriage.”

Among other things, an advance copy of the five-point pledge provided to CNN calls on candidates to support a constitutional amendment.

The National Organization for Marriage issued a similar marriage pledge in the 2012 Republican presidential primary, which was signed by most of the candidates including eventual nominee Mitt Romney.

Brown said his organization would send the pledge to the publicly announced GOP candidates on Thursday with a request for it to be returned within two weeks.

Potential GOP candidates such as New Jersey Gov. Chris Christie, Louisiana Gov. Bobby Jindal, Ohio Gov. John Kasich and Wisconsin Gov. Scott Walker would be sent the pledge to sign once they formally announced their intentions to run for the White House.

“Our hope is that as many candidates as possible sign, 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,” Brown said. “So whether we end up having four candidates or 15 we are going to support he candidates that stand up and sign the pledge.”

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