International observers must be astonished that Australian politics is tearing itself apart yet again. With Prime Minister Abbott's leadership now seemingly in near-terminal decline in the wake of his decision to award a knighthood to Prince Philip, Australia's 'coup culture' has returned. In fact, it never really left. As the astute anonymous blogger and tweeter The Piping Shrike points out, 'Basically in five years we have had about 8 months when the PM hasn't been "embattled".'

Although this is largely a domestic farce (or is that tragedy?), it has a decidedly international dimension.

Paul Kelly's account* of the 2009 leadership spill that deposed Malcolm Turnbull and brought Tony Abbott to the leadership and eventually the prime ministership argues that climate change was at the core of the leadership contest. Turnbull wanted to deal with the Rudd Government on an emissions trading scheme, but Senator Nick Minchin threatened that this would lead a dozen Liberals (and the entire National Party) to cross the floor, resulting in the most significant internal split since the Liberal Party's founding. The dispute over climate change 'went to the identity of the party', says Kelly.

When Turnbull called for a vote on the leadership in late 2009, Abbott put himself forward as a candidate who would oppose emissions trading and thus hold the party together. He won the ballot by a single vote.

Now, we are told, Malcolm Turnbull is a leading candidate to replace Tony Abbott as Liberal leader and prime minister, thus raising again the ideological split that led to Turnbull's downfall in 2009. Phillip Coorey writes:

While members of the junior ­Coalition partner have no say in who leads the Liberal Party, some have sought to remind the Liberal Party that the Coalition nearly fell apart in 2009 just before Mr Turnbull was ousted as leader and replaced by Tony Abbott. The Nationals played a significant role in Mr Turnbull’s demise by running a guerrilla campaign against his intention to do a deal with Kevin Rudd on an emissions trading scheme. So poisonous did the relationship become that by the end of Mr Turnbull’s reign, the Nationals were threatening to quit the Coalition and many Liberals were willing them to go.

And here's Paul Kelly today:

As for Turnbull, he brings three serious defects to the job. Many MPs believe he cannot hold the Liberal Party together, that it would shatter under his leadership in a 2009 replay and that his progressive values will fracture the conservative side. Second, the Nationals distrust him, thereby creating a coalition friction. Third, Turnbull cannot crusade against Labor’s carbon pricing policy, a big problem.

In Turnbull's favour is the fact that the international ground has shifted appreciably on climate change since 2009. In fact, that shift happened in part right here in Australia when President Obama last November gave a blistering speech on climate change in Brisbane which rocked the Abbott Government with its thinly veiled criticism of the Government's climate-change stance. Obama was on a roll after signing a major emissions agreement with China just before he arrived in Brisbane. Coalition governments always pride themselves on their fidelity to the US alliance, and this was a pronounced breech — in the history of the alliance, had there ever been such an obvious difference in sentiment on arguably the major international issue of the day?

Should the Liberal Party return to Turnbull, he would probably have to soften his stance on climate change to mollify the right of his party and the Nationals. But how? His political persona is framed around his principled stance on this issue. As he said in 2009: 'How can I change the principles I have championed? What reputation would I have left?' (UPDATE: Lenore Taylor sees a way out of this dilemma.)

Should the party stick with Abbott, it will for the time being continue to be able to suppress its internal divisions on climate change. But for how long? If the international momentum created by the US-China agreement last November continues into the Paris conference in November-December, we might just get that elusive legally binding  and universal agreement on emissions. That still looks an unlikely bet, but should it happen, it would make Australia's stance look even more anachronistic than it does now.

It's not unprecedented for issues with an international dimension to split major Australian political parties — it happened to Labor in the 1950s when it split over communism. Could climate change do the same for the Liberals?

* Most articles from the Australian are paywalled. To get around it, just Google 'How the Liberals were reborn in the party crisis of 2009' and click on the top link.

Photo courtesy of the Liberal Party.