Possible GOP presidential candidates Rick Santorum and Mike Huckabee are among those who signed a pledge to defy a Supreme Court ruling striking down state bans on gay marriage.

The nation's highest court will hear oral arguments in a case challenging bans in four states – Ohio, Michigan, Tennessee and Kentucky – on Tuesday, with a ruling expected in June.

Signers to the pledge promise to “stand together in defense of marriage,” claiming that a ruling allowing nationwide same-sex marriage would hurt children.

“As a policy matter, such unions convey the message that moms and dads are completely irrelevant to the well-being of children. Such a policy statement is unconscionable and destructive. Authorizing the legal equivalency of marriage to same-sex couples undermines the fundamental rights of children and threatens their security, stability, and future,” the pledge states.

A ruling favoring plaintiffs would be wrong, they said, comparing it to the Dred Scott decision of 1857 which said that Scott, a slave, could not buy his own freedom.

“The Supreme Court was wrong when it denied Dred Scott his rights and said, 'blacks are inferior human beings.' And the Court was wrong when Justice Oliver Wendell Holmes wrote in Buck v. Bell, 'three generations of imbeciles are enough,' thus upholding Virginia's eugenics law that permitted forced sterilization.”

“In these earlier cases, the definition of 'human' was at issue. Now the definition of 'marriage' is at issue. The Constitution does not grant a right to redefine marriage – which is nonsensical since marriage intrinsically involves a man and a woman. Nor does the Constitution prohibit states from affirming the natural created order of male and female joined together in marriage.”

“We will view any decision by the Supreme Court or any court the same way history views the Dred Scott and Buck v. Bell decisions. Our highest respect for the rule of law requires that we not respect an unjust law that directly conflicts with higher law. A decision purporting to redefine marriage flies in the face of the Constitution and is contrary to the natural created order. As people of faith we pledge obedience to our Creator when the State directly conflicts with higher law. We respectfully warn the Supreme Court not to cross this line.”

Along with Huckabee and Santorum, signers include former House Republican leader Tom Delay and Focus on the Family founder James Dobson.