The Greens might have lost their political innocence when it entered an alliance with Labor, but offering support to the conservatives is another matter entirely, writes Mungo MacCallum.

The Abbott Government has no shame. This is hardly news but it is good to see it confirmed, yet again, by the deal with the Greens to abolish the debt ceiling in exchange for some largely meaningless and easily avoided undertakings about transparency.

This time last year dealing with the Greens in any form was akin to selling your political soul. Julia Gillard's alliance, first with Bob Brown and then less comfortably with his successor Christine Milne, was excoriated, anathematised by Abbott and his colleagues; no sane or decent person could associate with these fanatical destroyers of Australia's wealth and freedom.

Even after Milne formally dissolved the alliance, the attacks continued: the Greens had invaded the Gillard government like a malign, alien parasite and were still controlling their hapless and gullible hosts. The Greens were the enemy of all the Australian way of life; it was as simple as that. Any contact, however fleeting and superficial, risked contamination.

And dealing with them was invariably and irrevocably lethal. But only, apparently, for a Labor government. The hardy conservatives are immune. And anyway, it is all about outcomes, the end justifies the means. So our dauntless Treasurer Joe Hockey had no real hesitation in following the Faustian example.

And the pact he made was almost entirely one-sided; it did not even require his signature in blood. The debt ceiling was no more; never again would he have to go begging to Parliament for a rise, or endure the taunting and posturing of an understandably cynical opposition which had endured three years of thundering about the horrors of debt and deficit.

The economic crisis was officially over, and so was the political one which had accompanied it. It was the first real win for the Government since its election, and Jockey and Abbott had every right to feel smug about it. Hypocrisy, shmypocrisy. Whatever it takes. There will be no sleepless nights on the government benches.

But for the Greens, and for their leader in particular, it may not be quite so simple. Debt in itself has never been a real issue for them; the concept is fine, even desirable, if it is used for long-term projects and worthwhile purposes like improving infrastructure - sustainable infrastructure, that is - and the promises of reporting to Parliament and justifying government decisions look, at first glance at least, like a decent sort of quid pro quo. And by sitting down with Hockey, they have thrown off the label of being economic fringe dwellers; they have entered the political mainstream. But that may be exactly the problem; there is, after all, a terrible precedent.

In 1999, John Howard was desperate to pass his Goods and Services Tax. His resurrection of the "never, ever" GST had nearly seen him defeated at the 1998 election and his political credibility now depended on getting it through a hostile Senate. Labor and the Greens were implacably opposed and to Howard's dismay, the independent Brian Harradine, on whose support Howard had been relying, also opposed it.

His only hope was the Australian Democrats, and he turned to their leader, Meg Lees. The Democrats had campaigned in 1998 under the slogan of No GST on Food, and Lees took this as a licence to negotiate, saying she could make a bad tax better. In fact, exemptions destroyed the whole point of the tax, the efficiency resulting from its universality. However, Lees demanded and received a number of concessions on what she called "the necessities of life", a term which invited ever further widening of its inclusions. Eventually the list was finalised and Lees announced the Democrats would support the new package.

But many of her supporters were furious; some were opposed to the tax in any form and others felt Lees should have fought harder for items such as books to be exempted. The parliamentary party split: two of the nine Democrat senators, Natasha Stott Despoja and Andrew Bartlett, crossed the floor to vote against the GST. Among the rank and file, the reaction was wider and more vehement. They called a leadership spill, as the Democrats constitution allowed, and although Lees survived the first attempt, a second in 2001 saw her replaced by Stott Despoja. A year later she resigned from the party altogether.

The dispute was the beginning of the end. In the 2001 election, the Democrats only lost one senator, but in 2004, after more leadership turmoil and grass roots disillusionment, they lost three. Of the remaining four, two did not contest the 2007 election and the other two lost their seats. As a viable force, the Democrats were finished.

In hindsight, it was clear that the trigger for their decline was Lees' agreement with Howard. He wooed her with the promise that it would make her party relevant, part of the processes of government. But that was precisely what rank and file Democrats did not want. They gloried in the fact that they were outsiders, unsullied by compromise. Their role was, in the words of their old slogan, to keep the (other) bastards honest. Lees should have been frustrating Howard, holding him to his 1996 promise that he would never, ever introduce a GST. They felt betrayed and although many hoped that Stott Despoja could restore the party's political virginity, when she failed, they threw in the towel.

OK, the parallels are not exact: the Greens have a much more solid base than the Democrats and rather more resilience. And they are no longer pristine; by aligning with Gillard in 2010, they well and truly lost their innocence.

But Abbott is not Gillard; he is, unequivocally, the enemy. If Milne is to offer him any solace at all (and there will be many on the party who think that she should refuse to piss on him if he was on fire) then the price should be a steep one; after all, look at what Brown extracted from Gillard.

At the very least, Milne's deal will be the cause of a certain amount of dissension in the party, and she is not without rivals who will welcome the chance to undermine her. If she is again to sup with Abbott, she would be wise to take a longer spoon in future.

Mungo MacCallum is a political journalist and commentator. View his full profile here.