Ex-US Senator, Rick Santorum, has joined the campaign against equal marriage in the state of Washington, and has said that if it became a reality, churches and families would be destroyed.

The former Republican presidential candidate said that marriage would “disintegrate” if equal marriage became law.

He was addressing the audience at a closed-door Spokane fundraiser for the Family Policy Institute of Washington, an anti-marriage equality group.

On November 6, a referendum will take place on whether equal marriage should become law in the state of Washington.

A link to the video of Mr Santorum’s full address was posted by SeattlePI.

“This is a turning point in American history and, yes, the state of Washington,” he said.

“The movement you are fighting is the most important movement to win,” he said, “This issue will destroy and undermine the church in America more than any other movement,”

Mr Santorum warned that the fight against equal marriage rights was more important than the anti-abortion battle, and that marriage, and the American family, would “disintegrate” if equal marriage became law.

He described opponents to the referendum as “on the side of truth,” and said: “You folks are in the front line. You folks are in the foxhole.”

He said that Western European countries were “declining” because of “a secular revolution, a godless revolution”, which threatened to spread to America and “destroy the institutions of America’s foundation, destroy the American family.”

Mr Santorum talked about the “normalisation, acceptance, tolerance,” of LGBT people since the 1990s, and said: “This will be the norm in America,” he said, “this is what you are fighting. You are on the front lines.”

Maine and Maryland will also be voting on marriage equality on November 6. At the same time, Minnesota voters will choose whether to make a constitutional amendment which would define marriage as only between one man and one woman.

A group of 63 ex-Catholic priests in the US state of Washington are due to announce their support for Referendum 74, the vote on equal marriage in the state, which will take place next month.

A poll last week, showed Washington voter support for equal marriage in the referendum at 57%.