The ongoing argument over why Peter Dutton lost the McPherson preselection on the weekend is, as far as I can tell, being driven by two factors.

One is what can be generally lumped under the heading “Brandis disaffection.”  There are a number of ex-Liberal (now, to their chagrin, LNP) MPs and Senators who objected to the Liberal-National merger from the get-go, worked hard against it and swore it would have disastrous consequences.

The defeat of Dutton (who started off opposed to the merger, then swung behind it with enthusiasm when it looked unstoppable) is being used by those forces – primarily represented by George Brandis – as an example of exactly the sort of consequences they predicted: the Nats have taken over and are pursuing their own vindictive agenda against the Liberals, at the expense of unity.

The other is what seemed to be an Australian-based campaign to play up the problems with Malcolm Turnbull’s leadership, by portraying the preselection outcome as a direct attack on his authority, given he supported Dutton.  Peter van Onselen, whom I normally don’t mind as a political observer on the Liberal side, today continued the line, which Glenn Milne has also pushed, that Dutton was the victim of a Nationals plot.  Van Onselen was also behind what I regarded as a misleading “survey” of backbenchers last week that established the obvious point that most backbenchers didn’t want to negotiate with the Government before Copenhagen – something which is in fact party policy anyway.

It was also amusing that Dennis Shanahan insisted a couple of time that the today’s disastrous Newspoll showed the Nationals’ vote holding steady (reflecting the success of the Nationals’ anti-ETS stand), when in fact it went from 5 to 4.  For those so disposed, that’s a shock 20% collapse…

Dutton was dudded not by the Nats buy by his fellow Liberals, who wanted a Liberal, and his own poor judgment. Some Nats actually voted for him. The only plot is in the minds of News Ltd commentators.