Things are pretty miserable for Labor at the moment but Tony Abbott’s plebiscite stunt should give Labor MPs brief reason to smile. Just for once, it says a lot more about Liberal thinking than it does about the Government.

For one thing, it was handled with almost Labor-like ineptitude. If the plebiscite idea had seen daylight months ago, it would have made for a nice hand grenade chucked into the carbon price debate. Instead, it was left until the valedictory speeches were already flowing in the soon-to-be-rather-Greener Senate. There was no consultations with the independents in the Reps or Nick Xenophon and Steve Fielding; the latter declared the proposal a stunt and rejected it this morning, after Tony Windsor and Rob Oakeshott rejected it yesterday.

And Abbott’s staff hadn’t done the basics in preparing his talking points. That meant he ended up being wrong about when he could introduce the bill in the Reps, and wrong about the cost — his initial costing was based on the 1999 republic referendum, meaning his figure was 10 years out of date. And apparently no one thought to ask the simple question about whether the Liberals should feel honour-bound to respect the plebiscite result like they wanted the Government to be. Abbott tripped over himself trying to explain what he’d do if his question — framed naturally to yield a “No” vote — met with unexpected success.

The Liberals also needed to be careful since it’s less than a year since they were attacking Gillard’s idea of a citizens’ assembly as undermining the right of Parliament to determine policy.

While that was unfolding, the unlikely figure of New Zealand’s John Key was affording a glimpse of the Liberals’ worst-case scenario. Key spoke about how effective the Kiwis’ emissions trading scheme had been and how he wanted to link up with an Australian scheme. He also noted how business support for the scheme was growing — interesting because much of “New Zealand business” is actually owned by Australian companies.

Abbott did what he regularly does at supposedly apolitical occasions and injected a partisan note into his address to Key in Parliament, implicitly rebuking him for failing to ditch the ETS. It wasn’t merely inappropriately partisan, or further evidence that Abbott lacks class, but downright rude to an honoured guest.

It isn’t just New Zealand that has discovered that once an ETS is in place, business hysteria over it vanishes. That has been the experience under the European scheme, now six years old, and under the UK’s pilot trading scheme; when visiting Australia in March, the European Commission’s Jill Duggan spoke of convention centres full of business representatives attending consultations before the introduction of the scheme turning into virtually empty consultations once it was in place.

What makes it worse for the Coalition is that the Government’s scheme will include at the very least increased payments to pensioners and low income earners, and possibly some tax cuts, which will either have to be withdrawn on the repeal of a carbon pricing scheme or offset by big spending cuts elsewhere.

That’s why an Abbott Government would make an at-best halfhearted attempt to repeal the scheme, but not press the issue when the Greens used the balance of power in the Senate to defeat the repeal bill. Honour would have been satisfied — the Liberals would have tried to repeal it, but failed, and thereafter could quietly get on with life under an emissions trading scheme.

But all that’s after the next election. Once a carbon pricing scheme is legislated, Tony Abbott is committed to going to that election telling about half the population they’ll have money taken from them, or explaining what parts of the Budget he’ll slash to keep the payments flowing. Combined with the likely criticism from business, and the reality of a functional scheme, it’s a deeply problematic outcome for Abbott, though not for Malcolm Turnbull or Joe Hockey.

That’s why Abbott is so desperate to stop the legislating of a carbon pricing scheme, desperate enough to conjure up a back-of-the-envelope stunt like a plebiscite — anything to try to halt any momentum toward a deal between the independents and the Greens and Labor on carbon pricing. The day a carbon pricing scheme is legislated, if it is, life gets harder for Abbott — and harder still on 1 July next year.

It’s unlikely to be enough to save such an inept Government at the next election but it’ll be a terrible headache for the Liberals, and risk reawakening the long-suppressed divisions over those who actually want to address climate change, and the denialists and opportunists who don’t want to do anything.