The lock step between the major political parties over Australia's continued presence in Afghanistan has effectively neutralised the war's potential to politically damage successive Liberal and Labor governments.

So far. But sniff the political wind today and you might just smell the potential for change.

Afghanistan remains an immensely unpopular war with Australians.

Thirty-two Australian Defence Force personnel serving in Afghanistan have been killed. Hundreds more have been wounded.

Astonishingly, four of those fatalities have occurred at the hands of members of the Afghan National Army, which Australia is mentoring so the corrupt government of Afghanistan just might stand a chance, at some point, of securing itself from the Taliban and other insurgents.

The attacks on Australian troops by Afghan army members have pushed some who had been lending considered support to Australia's continuing role in the conflict to reconsider.

Until quite recently, the loud, dissenting voices on Afghanistan largely came from the left, as represented by the Australian Greens, who have consistently and vociferously opposed the war. There has been little public dissent, however, in the Labor or Liberal parties.

But any marked change to that position could transform Australia's Afghanistan deployment into a much more divisive, rancorous and high-stakes political issue.

Some prominent conservative spear-throwers have for some time been succinctly articulating their own arguments as to why Australia should withdraw from Afghanistan. Alexander Downer has said that Australia is becoming stuck in an unwinnable war. He argues that Australia's original objectives of destroying al-Qaeda after the terrorist attacks on the US on September 11, 2001, have largely been achieved. Downer remains a hugely influential conservative thinker, especially on diplomatic and defence issues, in his party.

Prominent voices in the conservative commentariat, not least Tom Switzer, a would-be Liberal MP at the University of Sydney United States Studies Centre, also advocate Australia's departure from Afghanistan. While it pains me to concur with just about anything he says about anything, I agree with tough-guy Tom's assertion that the so-called special US-Australia relationship would survive if Australia pulled out of Afghanistan.

''Well, I think the alliance would wear that very well. I mean, the Canadians have pulled out - are in the process of pulling out of Afghanistan - so have the Dutch. The British - David Cameron, the Prime Minister, has made it clear to the President that the British want out as soon as possible. I suspect their special relationship will also prevail.''

In June, the conservative foreign policy commentator Greg Sheridan, once a strident supporter of the Afghanistan war, wrote in his newspaper, The Australian, after the deaths of two more Australians (one of whom was killed by an Afghan army member), that the federal government should cease its military training program with Pakistan and withdraw from Afghanistan within a year. Why? Because America and its allies cannot win the war in Afghanistan while Pakistan covertly supports the Taliban. Pakistan's support for the Taliban is long established. So what's changed?

Well, it seems conservative flag bearers are increasingly coming to the view that many others have long held: it is morally unjustifiable to risk Australian soldiers in a war that can't, in any conventional sense, be won. That Taliban-influenced Afghan army soldiers are now killing the Australians who are training them makes this point even more obvious.

Such views are much closer to mainstream Australian sentiment on Afghanistan than the poorly explained or justified policy of continued military engagement that currently has bipartisan political support.

It is an argument that could readily be adopted by Tony Abbott who, as Liberal leader, has displayed a craven willingness to oppose government policy for pragmatic political reasons alone.

The political virtue for a Liberal leader of the anti-Afghanistan policy, as it is now being articulated by some conservative voices, is that it cannot easily be dismissed by the pro-war right as merely an ideological leftist anti-war rant.

Abbott, having just returned from Afghanistan, will be sharply attuned to the havoc he could wreak should he change Liberal positioning on Afghanistan.

War. Australian lives. The national interest. They are big issues. And they are worthy of a big argument.

The dogs are barking. But will they bite?

A sudden rush for the exit?