A coalition of conservative groups in the US have vowed to defy any ruling made by the US Supreme Court next week in favour of equal marriage.

The US Supreme Court failed to announce its opinion on two key equal marriage cases on Thursday, and is now expected to do so on Monday, which is the last scheduled date to make a decision.

The court could rule on Proposition 8, California’s state-wide ban on equal marriage, and the Defense of Marriage Act, which federally bans same-sex married couples from benefits afforded to opposite-sex marriage couples.

In a letter released on Thursday, over 200 conservative opponents to equal marriage, vowed to ignore any ruling by the Supreme Court in favour of a same-sex marriage.

The letter was signed under the collective title, Freedom Federation, with the slogan “real hope, real change, real freedom”, and is made up of prominent, and adamantly anti-gay Christian conservatives including Oklahoma State Representative Sally Kern, the Catholic League’s Bill Donohue and the Liberty Counsel’s Mat Staver.

“We stand in solidarity as Christians in defense of marriage and the family and society founded upon them,” the letter reads.

The Marriage Solidarity Statement, was drafted by Mat Staver, of the Liberty Counsel, and Deacon Keith Fournier, the editor in chief of Catholic Online. It attacks efforts towards equal marriage, in an attempt to preserve “natural moral law”, and questioning the authority of the Supreme Court.

“This Natural Moral Law gives us the norms we need to build truly human and humane societies and govern ourselves. It should also inform our positive law or we will become lawless and devolve into anarchy,” reads the letter.

“Redefining the very institution of marriage is improper and outside the authority of the State. The Supreme Court has no authority to redefine marriage.”

Despite threatening to disobey whatever ruling the court makes, the letter does not go into detail about how they will do so.

Some have noted that their intentions are unclear, because their churches do not perform same-sex unions, and because they do not directly work in the wedding business, or have the responsibility of granting marriage licenses.

The Supreme Court does not announce which decisions it will announce ahead of time. Monday 24th June remains on the calendar as the final day on which the court could announce a decision. It could however, add extra decision days after Monday.

On the first day of hearings in March, the court heard arguments around Proposition 8, the state of California’s ban on equal marriage. Then the justices questioned the meaning of marriage, and challenged arguments for the ban.

On the second day of hearings, several of the Supreme Court Justices raised concerns around DOMA, and some took that as a sign that there may be a narrow majority who will strike it down.

The full letter from Freedom Federation is available to read here.