Few things tweak the patriotic nerve of Australians more strongly than being outstripped by their trans-Tasman neighbours, New Zealand.
Traditionally, the rivalry plays out on the sports field. Yet this month has seen a kind of legislative equivalent of the Bledisloe Cup, the annual rugby union clash between the All Blacks and the Wallabies.
Rather than out-muscle the Australians, the Kiwis have out-reformed them.
They did so by becoming the first Asia-Pacific nation to legalise same-sex marriage.
In a country famed for its Maori hakas, the moment that the bill became law was celebrated in impromptu song: an Edelweiss moment, where the public gallery, then the well of the chamber itself, joined in a stirring rendition of the New Zealand love song, "Pokarekare Ana," sung in the indigenous tongue.
Not only did it became an instant YouTube sensation but it also highlighted the quietness on the issue from Australian parliamentarians. When last September the most recent gay marriage bill was put before the House of Representatives in Canberra, it was defeated 98 votes to 42.
As if to emphasise the distance between the two neighbours on this question, the reform came from a conservative government led by Prime Minister John Key, whereas Australia's Labor leader Julia Gillard remains opposed.
Now the embattled Ms Gillard is under heightened pressure to shift her stance, although she has publicly reaffirmed her opposition since the historic vote in Wellington.
Still, given most commentators believe she will suffer a landslide defeat in September's election, some supporters of same-sex marriage think she will not want to go down in history as perhaps the last Labor leader to oppose marriage equality. Her party, the ALP, is already officially in favour, though its policy is not binding either on the leader or her MPs.
'Worth 1.3m votes'
With or without her backing, Australia appears to be experiencing a transitional moment on this issue. Here, as was recently noted of America, the advocates of same-sex marriage have not yet won, but there is a mounting sense that its opponents have lost.
"Those who agree with same sex marriage have gone from being in favour to being strongly in favour," says Rodney Croome, the national convenor of Australian Marriage Equality. "Opponents have gone from 'strongly opposed' to 'opposed.'"
In both the pro- and anti-camps, he claims, there is a growing sense that reform is inevitable.
Polls suggest that almost two-thirds of Australians support same-sex marriage, compared with just 38% in 2004.
Backing is especially high among young people, 81% of whom are thought to agree with marriage equality.
"These are people who take concerns about gay marriage into the voting booth," says Mr Croome. "They don't just support it, they passionately support it."
He predicts that the first of the two major political parties to embrace same-sex marriage could reap a political dividend of 1.3 million votes.
"This is a vote-winner, not a vote-loser," he claims. The Australian Greens, led until last year by an openly gay Senator, Bob Brown, are already strongly in favour.
Many same-sex marriage advocates have given up already on Julia Gillard and are looking beyond the election, and the strong likelihood of a conservative government.
"Like most Australians we are looking at the possibility of an Abbott government, and realise that we need to speak directly to conservatives," says Rodney Croome.
"This is a not a left-right issue. There are many conservative arguments for reform: chiefly, it's about individual freedom and the strengthening of relationships and the family."
For reformers, it helps that a number of leading conservatives have either voiced outright support for same-sex marriage or called for a conscience vote in parliament where lawmakers would be allowed to make up their own minds.
The most significant backer is Barry O'Farrell, the premier of New South Wales and arguably the country's second most powerful conservative politician, who voiced support earlier this month. Malcolm Turnbull, the former Liberal leader, is also a supporter. Colin Barnett, the influential premier of Western Australian, remains opposed but thinks that MPs should be allowed to vote their conscience.
The Liberal leader Tony Abbott, a former seminarian whose Catholicism is an important part of his political make-up, recently signalled a new openness to the idea of a conscience vote should he become prime minister.
Recently, two of his daughters spoke out in favour of reform. His sister, Christine Forster, is very open about the fact she is in a same sex relationship.
Washington and Wellington
A shift in Republican thinking in America has also created an intellectual milieu among Australian conservatives far more receptive to change.
The fact that New Zealand conservatives gave such vocal backing to same-sex marriage is also significant.
The now famous parliamentary speech by the 63-year-old conservative National MP Maurice Williamson mocking the notion of some "gay onslaught" - which, like the song, also became a viral hit - has reverberated here. It was the precisely the kind of gruff, plain speaking that appeals to Australians.
Less instrumental has been David Cameron's support for same-sex marriage.
Partly because of his "greening" of the Conservative Party, he does not have much bearing over an Australian conservative movement that includes leading climate change sceptics. In this debate, Washington and Wellington have had more of an impact than Westminster.
Tim Wilson, the policy director of the right-wing think tank, the Institute of Public Affairs, says there has been a sea-change amongst fellow conservative gays and lesbians. "Five years ago, the issue didn't matter to gay Liberals," he says. "Now it does. It's gone from a private matter to a public matter."
Practical rather than philosophical concerns have shifted the conservative mood, he reckons.
"When you get so many people coming out of the closet, it affects attitudes among mothers and fathers, brothers and sisters, and friends and relatives. It's become a real thing for people, based on personal experience. That comes to be reflected in our politics."
For many conservatives, he says, this is a basic question of fairness, more so than equality.
Religiosity, which is nowhere near as central to Australian politics as it is to American politics, is not as big an obstacle.
Indeed, an irony of the Canberra debate is that Julia Gillard is an atheist, whereas Barack Obama had to reconcile his newfound support for same-sex marriage with the Biblical teachings he had grown up to believe.
Australians overwhelmingly do not have a problem with an unmarried prime minister, who lives with her partner, Tim Matheson, in The Lodge. It is simply not an issue, as it would be, say, in America.
The polls suggest that a majority of Australians exhibit the same spirit of tolerance on the question of same marriage.