An expert witness who testified against the constitutional challenge to California’s Proposition 8 ban on same-sex marriage has publicly recanted his opposition to marriage equality.

David Blankenhorn, the founder and president of the Institute for American Values, was a key witness called to testify against same-sex marriage in the case of Perry v. Brown and authored a book ‘The Future of Marriage’ in 2007, making the case against same-sex marriage.

However on Friday the New York Times published an opinion piece by Blankenhorn in which he explained his change of mind, and why he, as a supporter of marriage, now supports the rights of same-sex couples to wed.

‘The time has come for me to accept gay marriage and emphasize the good that it can do,’ Blankenhorn wrote.

‘I don’t believe that opposite-sex and same-sex relationships are the same, but I do believe, with growing numbers of Americans, that the time for denigrating or stigmatizing same-sex relationships is over. Whatever one’s definition of marriage, legally recognizing gay and lesbian couples and their children is a victory for basic fairness.

Blankenhorn wrote that he had initially hoped the debate over same-sex marriage would have lead to heterosexual America recommitting to marriage as an institution.

‘But it hasn’t happened … if fighting gay marriage was going to help marriage over all, I think we’d have seen some signs of it by now,’ Blankenhorn wrote.

‘So my intention is to try something new. Instead of fighting gay marriage, I’d like to help build new coalitions bringing together gays who want to strengthen marriage with straight people who want to do the same.

‘Will this strategy work? I don’t know. But I hope to find out.’

Blankenhorn was one of the most prominent US opponents of marriage equality to argue their case from a non-religious perspective.