Today’s passage of the stimulus package is Nick Xenophon’s biggest stunt yet.

The reason why he voted against the package yesterday, and voted for it today, lies in state-based environmental politics and his desire to outflank the Greens. And he’s pulled it off.

First the others. The Greens negotiated a pretty useful deal with the Government using $400m saved by shaving the $950 bonus payments by $50. It might have been small beer in the context of the tens of billions being chucked about, but Bob Brown had reason to be pleased with what he’d extracted from Wayne Swan and Julia Gillard. He’d got the Government to reverse the Howard Government’s lowering of the liquid assets test threshold for unemployment benefits, $200m worth of grants to community groups and councils for local employment, which would have picked up some of Steve Fielding’s proposal for a local jobs package, the now-famous bike paths funding, and a number of others. There’s media commentary that the Government doesn’t know how to negotiate with minor parties. Well, both Labor and the Greens did a professional job yesterday.

Steve Fielding supported the package without seeming to have extracted any concessions. He did so reluctantly — quite reluctantly — but on the basis that it was better than blocking it. Fielding attracts plenty of abuse — I should know, having written some of it — but he takes his role seriously, despite lacking the resources to do it properly, and gets stressed because of it. Yesterday he made a sensible call under a lot of pressure.

Xenophon, however, has more important things on his mind than preventing Australia from going into recession. It’s only a few days since Glenn Milne was claiming Xenophon would baulk at the package because he agreed with the Coalition on tax cuts, but Glenn, unusually, seems to have been astray in his analysis, because Xenophon refused his support because of the Murray-Darling Basin.

The Greens have owned the issue of the Murray-Darling for years. Western Australian Senator Rachel Siewert worked assiduously on water issues and the Murray-Darling, until last July, when South Australian Green Sarah Hanson-Young arrived in the Senate. Hanson-Young has championed the fate of the Lower Lakes and Coorong since then, churning out press releases and initiating inquiries. Yesterday, the Greens convinced the Government to provide funding for bioremediation of the Lower Murray, meaning revegetation and mulch are used to prevent soil acidification, rather than the preferred Rann-Wong option of letting in seawater.

Xenophon, who was elected at the same time as Hanson-Young, has also been pushing the Murray-Darling issue. As a State parliamentarian, Xenophon had little to say about the issue, but began pushing it vigorously on his ascension — if it can be called that — to the Senate. Now he seems determined to show that anything the Greens can do, he can do better. Yesterday he wanted to bring forward $7b of the Government’s MDB package. The idea was utterly unworkable. It would have added a further $7b to the 2009-10 deficit, and spending that amount of money would have been impossible in a single year, unless Xenophon also wanted compulsory acquisitions on a truly vast scale. Xenophon’s rationale for not supporting the package — that the MDB was critical to it — was also nonsensical. The entire Australian agriculture sector is worth 2-3% of GDP, meaning the MDB is worth fractions of fractions of GDP.

It would have added a further $7b to the 2009-10 deficit, and spending that amount of money would have been impossible in a single year, unless Xenophon also wanted compulsory acquisitions on a truly vast scale. Xenophon’s rationale for not supporting the package — that the MDB was critical to it — was also nonsensical. The entire Australian agriculture sector is worth 2-3% of GDP, meaning the MDB is worth fractions of fractions of GDP.

But Xenophon’s real agenda is to extract a decent sum of money from the Government, and enjoy the kudos of being the saviour of the Murray-Darling. Xenophon tipped his hand yesterday afternoon when he backed the Government’s motion that the Senate adjourn until 9am this morning, to give him time to see how many zeroes he could get out of the Government for water buybacks and irrigation infrastructure.

He’s ended up with $900m, which is more than twice what the Government was offering him yesterday. He’s now king of the Murray-Darling, the man who wrested nearly a billion dollars from the Government for his state and an ailing river system.

It’s been another Xenophon stunt — on a massive scale. But at least it might put a bomb under Penny Wong, whose reluctance to take vigorous action on the Murray-Darling remains deeply concerning.

And everyone will get their cheques.