Tony Abbott has sought to broaden the debate about same-sex marriage into an all-out culture war. Credit:Lukas Coch Wolfson, a lawyer and professor who was founder and president of the group Freedom to Marry, was the architect of the campaign to legalise gay marriage in the United States, an effort that culminated with a Supreme Court decision two years ago that found in part that one group of Americans did not get to hold a vote to decide upon the basic human rights of another. He has been named by Time magazine as one of the 100 most powerful people in the world. Wolfson's victory might have looked sudden from the outside, but it was the culmination of years of campaigning in which Wolfson and supporters battled anti-gay-marriage activists in a series of state legislatures, where, as in Australia, conservative politicians introduced ballot measures in an effort to block gay marriage. In many of these states Wolfson's key opponent was a bloke called Frank Schubert, a Republican staffer turned freelance campaign consultant. Like Abbott, Frank Schubert is a deeply religious man of powerful conviction. Like Abbott he is intensely disliked by gay marriage activists. In another weird parallel, like Abbott, Schubert has a politically engaged gay sister with a partner and family who does not share his views. This week, says Wolfson, Abbott played straight out of Schubert's campaign playbook.

Evan Wolfson says he's seen Tony Abbott's tactics before. Credit:Chester Higgins jnr "He knows they cannot win on the merits of their argument," explains Wolfson, noting that Australians already overwhelmingly back gay marriage, "so they have to make the debate about something else." That's why Abbott announced that this was about political correctness and freedom of speech rather than gay marriage. Wolfson is not speaking figuratively. After Schubert won an unlikely battle to have a ban on gay marriage added to the California constitution in 2008 via a ballot measure, Schubert wrote a memo detailing his winning strategy. Wolfson can see its echoes in Abbott's opening salvo. Frank Schubert, a gay-marriage opponent who fought Proposition 8 in California. Credit:NYT The now notorious document was an article for Political Magazine in February 2009, in which Schubert and his co-author explain how they won despite Californians supporting gay marriage at the start of the campaign by about 60 per cent to 40 per cent.

"We needed to convince voters that gay marriage was not simply 'live and let live' – that there would be consequences if gay marriage were to be permanently legalised," Schubert wrote. "We reconﬁrmed in our early focus groups our own views that Californians had a tolerant opinion of gays. But there were limits to the degree of tolerance that Californians would afford the gay community. They would entertain allowing gay marriage, but not if doing so had signiﬁcant implications for the rest of society." In the US those "significant implications" became the arguments that "gay propaganda" would spread into schools, that once gay marriage was the norm other aberrant forms of marriage would follow, that religious groups would be victimised. It became the fraught concern for the wellbeing of bakers and marriage celebrants and wedding caterers. It was about anything but the right of a committed couple to marry. All of this is already in play in Australia, and was neatly summed up by Abbott on Wednesday morning.

But according to Wolfson there was a parallel campaign fought too. While mainstream politicians kept their hands clean, aware that outright homophobia doesn't wash anymore, a subterranean poison of invective followed the overt campaign, and this too will now by foisted upon Australian gays and their families. You can see it already if you care to dip your toe into online sewers, and elements of it have crept onto cable TV. On Tuesday night Bronwyn Bishop was on Sky News warning of bestiality and the killing of newborn babies. Of course, in the years since gay marriage was legalised in America, the only impact to society has been that some gays got married, and many who once feared the outcome have now changed their views. Today even a plurality of Republicans support gay marriage, 48 to 47 per cent, while 64 per cent of Americans back gay marriage, up from 62 per cent. "This is not some sort of experiment Australia is being asked to make," Wolfson says. "Around the world 1.1 billion people now live in 22 countries where gay marriage is legal."

In none of those countries have any of the dire warnings of those who would see it banned come true, despite Bronwyn Bishop's nightmares. Nick O'Malley is a senior Fairfax Media journalist.