So, can we assume that all that talk last year about a merger of the Liberal and National parties is not going to produce anything?

The National Party, which is notionally led by Warren Truss but in fact led by Barnaby Joyce, has dealt itself out of the climate change debate, doing a disservice to its own constituency in the process. Bizarrely, it has left the task of protecting and assisting agriculture under the CPRS to the Liberal Party.

But then, that is only fair, because there are more regional and rural Liberals than there are Nationals.

It was the same story on wheat in 2008. The Liberals stood up for the interests of all wheat growers, while the Nationals advocated those of a narrow group of cosseted producers and a discredited company.

If the Federal Coalition is going to rupture, it would be better for the Liberal Party to control the process, rather than sit back and let it happen or, worse yet, allow Senator Joyce to control it.

At the moment the Liberals are reacting to Joyce, who clearly regards them as a permanent enemy with whom he is only temporarily aligned. The Liberals have their own problems, of course — chiefly a compulsion to fight internal battles out in public, and a weakened leader. But the time is surely coming when the Liberals must consider whether there are benefits in moving against the Nationals — standing in their seats, ejecting them from joint tickets, removing them from the shadow ministry — and bringing the continuing destabilisation to an end.