A former Republican Governor of Utah has come out in support of equal marriage, urging other Republicans to do the same.

Jon Huntsman was the first Utah governor to support civil unions for same-sex couples. and has now written that he thinks no Americans should be denied the right to marry.

He ran an unsuccessful bid to become the Republican Presidential nominee in 2012, and had only backed civil unions before that, however he said his stance on marriage had evolved, and his stance on civil unions “was four years ago”.

In a piece published in the American Conservative magazine, he wrote: “I’ve been married for 29 years. My marriage has been the greatest joy of my life,

“There is nothing conservative about denying other Americans the ability to forge that same relationship with the person they love.”

He went on to say that the Republican Party should ”start to lead again”, including urging its states to join the nine US states which currently allow equal marriage.

“The party of Lincoln,” he continued, “should stand with our best tradition of equality and support full civil marriage for all Americans.”

Huntsman had previously voiced his opinion on equal marriage, and said that he was opposed to that idea, but that gay people should be allowed civil unions.

“On marriage, I’m a traditionalist,” Huntsman said at a ABC News debate in January 2012. “I think that ought to be saved for one man and one woman, but I believe that civil unions are fair.”

The Supreme Court is due on 26 March to take up the case of whether to overturn Proposition 8, which in 2008 added a clause to the Californian constitution stating that marriage could only be recognised by the state if it were between a man and a woman, causing widespread controversy.