Like it or not, history will show it was Malcolm Turnbull - a Liberal Prime Minister - who presided over a renovation of the nation's outdated marriage law.
One might have expected such a modernisation to emanate from the left.
Yet perhaps this was the key. Think John Howard forcing new gun laws on a reluctant base or Labor's Paul Keating, dragging unions from the cloisters of centralised wage fixing to enterprise bargaining.
In politics, some reforms are only deliverable via the side closest to the constituency of resistance.
Appreciating these tricky politics goes some way to explaining why Malcolm Turnbull tucked himself in the Coalition peloton, leaving others to lead the breakaway.
His backflip to champion Tony Abbott's much-loathed plebiscite and subsequent embrace of Peter Dutton's benighted postal survey, had quickened his poll slide among middle Australians. But these same Australians would later participate in Dutton's survey in droves.
Turnbull made no secret of his support, but pointedly refused to drive the reform campaign. It made for a desultory process.
Even on the cusp of victory on Thursday, the PM sat back, husbanding his numbers nervously, abstaining on several conservative amendments, eager not to fuel resentments.
Turnbull formed the view that while marriage reform was possible, it would only be a political reality once the conservative side had played its last card - its insistence on full community consultation. Denying that step once demanded would invite legitimacy questions and raise the spectre of subsequent repeal.
Bill Shorten's role is under-appreciated here. When he pledged to legislate marriage equality immediately if elected, the calculus changed. Dutton and Mathias Cormann, Turnbull's conservative Praetorian Guard, concluded a promised plebiscite at the next election would not cut it.
The postal survey was their response. Not pretty, but pretty effective.
The untidy process is a reminder that all social reform is hard. And it is a reminder that it is hardest on the contemporaries involved whose real service and sacrifice is for those who come after. This has been true for workers surrendering months of pay to secure fair conditions, suffragettes losing their liberty and their lives to obtain the vote, and countless others.
Arguments will continue about the utility of the survey. Almost nobody in the LGBTQI community supported it and few now concede it was worthwhile.
Yet in the end, it forced the Parliament's hand. Nothing can now challenge this overdue reform and Australia is fairer for it.