Australia now, for the first time in our history, has a sitting Prime Minister, Deputy Prime Minister and Senate leader in favour of gay marriage.

It’s icing on a multi-layered victory cake for the LGBTI community, following the passage of legislation through the federal Parliament earlier this week to make discrimination on the grounds of sexual orientation, gender identity and intersex status unlawful under federal anti-discrimination laws — though religious exemptions still apply in all areas other than aged-care services.

Just as the leadership battle was wrapping up last night, there also came news of the landmark rulings in the US Supreme Court striking down the federal Defense of Marriage Act (DOMA) and California’s “Prop8” gay marriage ban.

The sweeping changes to marriage law in the US over the past year follow US President Barack Obama’s change of heart on same-sex marriage, and many would argue his public statement in support has been a significant part of that success.

Here in Australia, our newly sworn-in Prime Minister has undergone his own “evolution” on the issue. It was a long, controversial and personal road that led to Rudd posting a lengthy statement on his website in May detailing his new-found support:

“I believe the secular Australian state should be able to recognise same sex marriage. For me, this change in position has come about as a result of a lot of reflection, over a long period of time, including conversations with good people grappling with deep questions of life, s-xuality and faith.”

Rudd, a Christian, attributed much of his new position to a gay former political staffer — and Pentecostal — who made him rethink what constitutes a “credible Christian view of same-sex marriage”:

“[I]f we were today to adhere to a literalist rendition of the Christian scriptures, the 21st century would be a deeply troubling place, and the list of legitimized social oppressions would be disturbingly long.”

It’s a Christian perspective somewhat antithetical to the one held by Rudd’s elder sister, Loree, who first brought her brother’s views on the subject into the headlines in 2011. Loree Rudd quit the ALP when the party voted to enshrine support for marriage equality in its platform during its 2011 national conference. She wanted the issue put to a referendum and said there was a “global gay gestapo” that fed propaganda to lobby for marriage equality. She said at the time:

“The whole concept of equality comes from the Bible, from the sacred scriptures. All people are equal before God, but not all relationships.”

In July 2012, three marriage equality advocates, including former Australian Medical Association boss Kerryn Phelps, claimed Rudd had told them during the 2011 national conference that gay marriage “would have gone through” if he were still prime minister. They also claimed he said the reason Julia Gillard was in power was due to a deal she did with “the Australian Christian Lobby and [Shop, Distributive and Allied Employees national secretary] Joe De Bruyn”. De Bruyn has been an outspoken gay marriage opponent.

Rudd denied their version of the conversation, which reportedly took place at a party held by gay marriage supporters celebrating the party platform victory.

In any case, Rudd voted against Labor MP Stephen Jones’ same-sex marriage bill in September 2012. Whatever he might or might not have been saying privately, his public stance was clear. His change of heart last month raises plenty of questions about the issue’s future in Parliament. As we move towards the next election, the LGBTI community will be watching and hoping Rudd pledges to finish the work he began with his landmark same-sex relationship reforms in 2008.

It seems highly unlikely he would force Labor MPs to vote against their conscience on gay marriage in any future Parliament. He also said last month that he didn’t intend to take a leadership role on the issue, but that was as a backbencher and not as prime minister.

One day ago the national leaders of both major parties were firmly against any change to the Marriage Act. Following the US Supreme Court decision and a likely final vote in favour of full marriage rights in the UK in the coming weeks, Rudd now has the opportunity to make this a significant point of difference with both the Opposition Leader and his Labor predecessor.

*Drew Sheldrick is the editorial manager of CCH Parliament’s Political Alert service and the former national editor of gay and lesbian newspaper the Star Observer. He tweets at @DrewBoyTweets.