Whoosh whoosh whoosh … that’s the sound of gay and lesbian couples high-tailing it to Canberra in the wake of yesterday’s marriage vote, the nation’s more boring city about to get a lot more interesting. Also, the sound of wearied screenwriters dusting off their hilarious same-sex marriage comedy (Mass-I-do-ssetts, Hawaii He-llo!, Vermont Mezzanine) and running the find/change (‘Amsterdam’/’Manuka’) before shipping it off to Screen Australia.

The Labor + Green vote in the ACT assembly — so much for Labor and Greens not sharing values, danger to democracy etc etc — has become a cause for rejoicing across Left-liberalia throughout the land. No wonder — it is the sort of bold, decisive action that many people wanted to see from Labor, especially from Gillard Labor. The ACT Gallagher government’s move was principled no doubt, but it was also about striking a blow in the war within Labor over SSM, and its obstruction by the remnant Catholic Right.

Quite aside from pure animus, the Labor Right believe that SSM, though having net 50%+ public support overall, doesn’t have it in key marginal seats, and that being identified with it in the lead-up to the last election would have further endangered their real chance of success hahaha, while also identifying them too closely with the Greens hahaha. Hence Gillard’s bizarre mangled defence of her anti-SSM stance to a Left-field audiences during the Juliapalooza tour — she couldn’t say that it simply didn’t play in Punchbowl (though it may well do).

Indeed the celebrations over the move have been reminiscent of the, very moving, passage of a SSM bill in New Zealand, after which the “yes” voters sang a Maori love song. That moment, and Katy Gallagher’s strong and forthright defence of the bill — relief to hear a Labor person talking about something other than Labor — put the strongest argument for SSM forward.

Nevertheless, amidst all the hoopla, the ACT decision, and the Abbott government’s decision to challenge it in the High Court, this is not without problems for the progressive forces. We have for decades relied on the idea that our commitment to universalism means a commitment, within a federation, to federal power over state power.

From the Harvester judgement of 1907 through the failed federalising referenda of 1944, the 1967 referendum on Aboriginal affairs, and the 1984 High Court Franklin Dam decision, we have argued against the conservative notion that particular and local conditions, traditions etc should be allowed to exist in defiance of rights.

“Causes that claim a universal right demand a universal approach. In a federal system that is at the federal level, for something such as marriage …”

But now Gallagher is not only arguing that states and territories should have the right to decide on the nature of marriage as they see fit, but that such changes should be applicable right across the nation. That is a double-blow to a federal/universalist politics, since it implies that particular state/territory arrangements should be able to carry over to the whole country.

In arguing that the Abbott government should step aside from a High Court challenge, Gallagher argued that her government was simply doing “something” about discrimination — as if they were addressing an archaic law left on the books by oversight. That’s not really the case; SSM simply didn’t get past a higher Parliament, and the ACT move amounts to something of a run around the back of it.

The upshot of that politics is very tricky. First, it seems to open the federal system up to pure contradiction. For, if tomorrow, a conservative state passes a US-style defence of marriage Act expressly ruling out recognition of SSM, what then? Surely SSM advocates would want the High Court to strike such laws down?

Thus it has gone in the US, but there is one big difference. For all its states rights talk, the US has a strong federal constitution, strengthened by various amendments. Above all, the 14th, guaranteeing “equal protection”, the mechanism used to strike down California’s anti-SSM provisions. There is nothing of that power in our constitution, a feeble document most concerned with rail gauges.

Thus, aligning the Left, or progressives, with the “particularist” side of federalism is fraught with challenges. At root, it’s internally contradictory, and that contradiction would arise when progressives find themselves on the federal side of arguments. If a state wanted to institute its own labour provisions of a neo-liberal severity beyond existing federal frameworks, we would rightly slap them down, even if there was a substantial degree of consent within the state.

We would do so on the grounds that we are one nation, that people move around to work, and that standards should be universal (if a state wants to offer better standards, that’s fine, let business make the challenge against). Such universalism at the national level, expresses the universalism of the issue itself. Everyone labours, or may have to.

That universalism is encoded in SSM — indeed that’s what’s appealed to in the notion of “marriage equality”. The anti-SSM movement, by contrast, appeals to particularist notions; that marriage is an incommensurable institution, based around gender difference, childbirth, and the junction of nature and culture.

I would venture that the anti-SSM movement is going to get more of a dividend out of a High Court decision mandating marriage definition powers to the states, than the SSM movement is. Part of the problem in making this clear is the dunderheaded arrogance of the SSM movement, in presuming their argument to a be a universal truth, rather than a political cause, to be advocated and won — not as a simple tidying up of rights, but as a fundamental shift in human arrangements.

Causes that claim a universal right demand a universal approach. In a federal system that is at the federal level, for something such as marriage which requires transferability across borders. Whatever happens in states, the SSM movement shouldn’t focus on state-by-state battles, but go for the big win, a federal law — and then leave the conservatives to mount draining and backfooted attempts to preserve their position via states’ rights attempts. The ACT decision has cheered many, who may well come to rue its paradoxical effects.

* Vermont Mezzanine opens at the Nova, Chauvel and Electric Shadows in 2014