Now in minority government, with his cabinet leaking against him, a citizenship question mark over some of his MPs, disastrous opinion polling, byelections looming, a reshuffle required to replace Scott Ryan and a palpable shift in sentiment regarding his leadership, Prime Minister Malcolm Turnbull could at least take some pleasure from the likely marriage equality result on Wednesday.

A win for Yes will pave the way for legislation bringing Australia into the early 21st century in the remaining parliamentary weeks of the year. It will have been an extraordinarily ugly way to achieve it, with significant hurt inflicted on LGBTI Australians, but Turnbull will be able to claim it as his own achievement.

That, of course, is what his enemies, and the diehard anti-equality MPs within his own ranks, are keen to deny him. The fallback position of the marriage equality deadenders is now to stretch out the legislative process as long as possible by inflicting a blizzard of amendments on Liberal senator Dean Smith’s marriage equality bill — which already contains ample protections for religious groups that are consistent with existing anti-discrimination laws — and to offer their own bill. The right’s James Paterson this morning unveiled his own, extraordinary bill which would legalise discrimination by anyone merely on the basis of what they claimed to believe.

No campaigners and the Abbott forces believe they can turn what would be the one significant achievement of the Turnbull prime ministership into yet another means to inflict damage on him — at a point when he is already badly weakened from months of citizenship chaos.

A strong Coalition performance in New England and Bennelong with a minimal swing against the government will, unfortunately, only hold the line for Turnbull, not boost his fortunes. Both should stay in Coalition hands, but expect to start seeing finely-calibrated talk of what size anti-government swing will be enough to put Turnbull under pressure — 2% good, 4% tolerable, 6% bad, 8+% disaster, etc.

With things looking so grim for Turnbull, the marriage equality legislation might be a good opportunity for him to strike back at the right and make clear that the Smith bill is the way forward and the government will not tolerate attempts to delay its passage, or use it to strip longstanding anti-discrimination protections under the guise of “religious freedom”. If that prompts a backlash from the right, all the better: Turnbull will have the backing of voters and be able to argue he has bent over backwards to support the party’s position on marriage equality. And having a fight always brings out the best in Turnbull — like Julia Gillard, he drops the prime ministerial waffling and sounds authentic and impassioned when someone has thrown a grenade at him. It might even remind voters of the man they were so delighted to see take the prime ministership in 2015.

Then again it might precipitate a move against his leadership. But that looks increasingly likely now anyway.