Nationals MPs and senators shook their heads as they filed into their party room on Monday, August 20.

They were gathering to consider the Government’s decision to abandon the National Energy Guarantee’s emission reduction targets.

It wasn’t that they had any real problem with then-prime minister Malcolm Turnbull’s announcement.

They overwhelmingly supported it.

It was the leadership frenzy behind the decision that caused the tut-tutting.

As the meeting was drawing to a close, the Nats began openly musing about whether Turnbull would survive the week.

Many thought they would soon be dealing with prime minister Peter Dutton. They didn’t mind that idea.

Then the black sheep of the mob piped up.

“You want to know who I think will win,” said Barnaby Joyce.

“Who?” someone replied.

“Scott Morrison.”

“But he’s not a candidate.”

“Not yet!” Joyce declared confidently.

The exchange might not appear in the official minutes of the meeting, but several Nats confirmed it to me this week.

And, built on another chance encounter I had with a second prominent Nat in that week of the Keystone coup, it suggests the Nationals knew a whole lot more about what was really going on inside the Liberal Party than most of the Libs themselves.

On the following Thursday night, as the Liberals were preparing for the likelihood of a second spill the next day, I bumped into NSW senator John “Wacka” Williams leaving the building for dinner.

Wacka is many things. He is a former shearer, though he’d probably dispute the “former” bit. And he is one of the Parliament’s fiercest advocates for farmers and rural business people.

He campaigned furiously against the banks and played a big role in finally forcing the Turnbull government to relent on a royal commission. On top of that, he’s the sort of bloke who calls an agricultural digging implement a spade.

So, when I asked him whether he thought Turnbull or Dutton would be prime minister by the following afternoon I knew I’d get a straight answer.

“Morrison,” he said.

Later that night, number crunchers on both sides confirmed to me that Morrison was, indeed, ahead on their early counts. Both could see Julie Bishop dropping out in the first round, with her preferences breaking heavily to Morrison, pushing him over the line.

That is, of course, exactly what happened.

The Nats were right.

But how did it get to that? It’s a question many Liberal backbenchers are still wondering themselves this week as Labor continued to pepper Morrison at least once a day with questions about exactly why he was now prime minister and Turnbull wasn’t.

The most honest answer has come, again, from a Nat. And not just any Nat. It came from their leader, Deputy Prime Minister Michael McCormack.

Asked that question on Sky News, McCormack replied: “Newspoll, ambition ... when you combine those things, people take the opportunities.”

McCormack probably regards that now as an unfortunate moment of candour.

But it’s still the clearest summation we’ve got.

However, it only answers the “why”. The “how” is more intriguing.

Several Liberal MPs think they now have an answer. It is one that owes itself to what John Howard would call the brutal laws of arithmetic.

It’s a phrase Turnbull found himself repeating with inadvertent poignancy in the days before his number was up.

The theory is that while Morrison was remaining publicly, vocally and huggingly loyal to Turnbull in the head-to-head battle with Dutton, his supporters were secretly doing their numbers to ensure Morrison would come through the middle in the final showdown.

The strategy lies somewhere between that of a chess master and a Napoleonic general.

It involves a phantom charge, the sacrifice of key pieces and, finally, a clear run for their king.

It’s now believed Morrison’s supporters voted in sufficient numbers to lift the Dutton camp’s tally in the Tuesday spill to a respectable and dangerous 35, with Turnbull on 48.

It was a tactical manoeuvre that made a second spill a certainty, ensured Dutton appeared a real threat but, crucially, fell short of delivering him enough support to actually win the vote.

When the second spill did come around on the Friday, the first ballot was a procedural vote on whether there should be a spill at all.

The emerging belief is that this is where Morrison’s supporters put the final phase of their plan into action, voting in greater numbers behind Dutton to ensure the procedural ballot got up, 45-40.

In doing so, they effectively put Turnbull’s leadership to the sword and gave Dutton the false hope that the final numbers would fall in his favour.

And then, the Morrison camp applied the double-reverse squirrel grip.

Those who had broken off to vote for the spill abandoned Dutton and made the decisive move to drive their full numbers in behind Morrison.

As a result Dutton polled 38, Morrison 36 and Bishop 11 in the first, three-way ballot.

Bishop dropped out. Nine of her numbers broke to Morrison and he won the head-to-head battle with Dutton 45-40 — the same result as the procedural vote.

It is a compelling version of events that suggests there was an impressive level of strategic artistry behind the apparent clown car pile-up.

Some in Morrison’s camp are now boasting that it is, indeed, exactly what did happen. Mind you, at the same time they are casting themselves as the tactical geniuses who called the shots.

We often find at such times that there are those hollow men (they are almost always men) who are quick to claim the mantle of master tactician and bathe in the rosette glow of their own brilliance.

Politics is full of such vertiginously vainglorious characters.

But this story does ring true.

And serious players are now finding some elusive coherence in its telling that might explain the true emergence of the “accidental” prime minister.

Perhaps there is really only one way to know.

We’ll have to ask a Nat.