Our say: This is a ‘killing season’ without a killing

Next week is the last scheduled parliamentary sitting week of the year.

It's the so-called "killing season" for prime ministers. It will bring a heavy seasonal onset of speculation about Malcolm Turnbull's future.

The speculation likely will be feverish. It is not a media confection. There is a growing sense of hopelessness besetting Coalition MPs and senators.

But Turnbull is not about to be replaced. Why not? We've been conditioned to expect it as part of a political reflex when a prime minister is in trouble. Parties kill off leaders as readily as you might clear your throat from some irritant.

Turnbull's time in office of two years and two months is already longer than the average of the past four prime ministerial terms – one year and 11 months.

So why not clear this irritant for showing "no leadership", as the leader of the NSW National Party, John Barilaro, urged on Friday when he called for Turnbull's resignation?

Here's why. There are four people in the federal Liberal party who are touted as potential replacements. The two with most support are Immigration Minister Peter Dutton and Foreign Affairs Minister Julie Bishop. Dutton is the champion of the party's conservative faction and Bishop of the moderates.

What has Peter Dutton been telling the agitated supporters who urge him to challenge Turnbull? "Our best chance is to make the Turnbull government a success," he has been advising colleagues. "We have to get back to work."

And when colleagues have sounded out Julie Bishop as a contender, she tells them: "I will never challenge Malcolm."

Neither is campaigning or organising for the prime ministership. You can't replace the prime minister unless you have a replacement. There isn't one.

Why the reluctance? They've seen the deep, enduring damage that a leadership coup inflicts.

It didn't work for Labor. The cycle of political violence unleashed when Julia Gillard tore down Kevin Rudd, who then tore down Julia Gillard, ended only in political failure and lasting bitterness.

The cycle of political violence unleashed when Tony Abbott tore down Malcolm Turnbull, who then tore down Tony Abbott, is heading perilously towards the same outcome.