Let’s start with numbers. Since the United States, backed by its allies including Australia, removed the Taliban from power in Afghanistan in 2001 in retaliation for the September 11, 2001 terrorist attacks on the US, 40 Australians have been killed in that country and 262 wounded.

Those numbers are dwarfed by American casualties – 2300 dead and more than 17,000 wounded since 2001. But the Australian toll is significant and should represent a cautionary note about further commitments.

Malcolm Turnbull visits the memorial at the Resolute Support Mission HQ Kabul, Afghanistan. 40 Australians have so far been killed in the long-running conflict. AAP/pool

All this is relevant in light of next week’s summit in Brussels, at which leaders of NATO powers will review developments in Afghanistan, including what might be done to bring a long-running conflict to a conclusion.

Top of the agenda will be the question of whether NATO forces need to be increased, and how significantly. That might mean a bigger American commitment than hitherto discussed publicly.

The number 50,000 is being canvassed in Washington to bolster the 8,400 Americans in the country. That is well up on a figure of about 5,000 that had been regarded as a likely commitment.

NATO-led forces in Afghanistan, including the Australians, number about 13,450.

Prime Minister Malcolm Turnbull has indicated Australia is considering adding to its deployment in Afghanistan in response to a NATO requestfor additional troops to help ramp up training of the Afghan military.

“We have been asked to consider additional resources, and we are actively considering that,” Turnbull said earlier this month after a visit to Afghanistan.

Numbers being spoken of are in the order of about 100 to add to the 270 already there. That commitment – if it materialises – would be small, but significant in the sense that it would reverse a draw-down that began in 2013 when Australian troops pulled back from forward positions in Taliban-infested Uruzgan province.

In all of this the question needs to be asked: what is the purpose of committing additional forces to a war that is now the longest-running in Australian military history, with no end in sight?

What is Australia’s interest in continuing to prop up a flimsy Afghan government – riddled with corruption – in control of barely half the country?

What is the end game? Or is there no end game beyond hoping that combatants fight each other to a standstill, and in the process improve prospects for a negotiated settlement.

Australian policymakers insist the Afghan military needs additional assistance, and if it is not forthcoming risks are the Taliban will overrun government forces.

They argue the best hope of a negotiated end to the conflict is for the Taliban be made to come to the negotiating table like other insurgent movements which have concluded military victory is no longer an option.

In Afghanistan there is no sign the Taliban is anywhere near reaching that conclusion.

In the 12 months to November, 2016 before winter effectively shut down hostilities, government uncontested control of territory fell to 57 percent from 72 percent a year earlier.

The Taliban is thought to be in control of something less than 10 percent of the country.

But the morale-sapping figure – from an Afghan government perspective – is the continuing high casualty rates. In the 12 months to November 6,700 Afghan troops were killed compared with 6,600 in the same period to November 2015.

This is a shocking attrition rate in a country whose military numbers less than 400,000.

On top of that the United Nations reports that 583,000 Afghanis fled their homes in 2016 due to conflict, the highest number since 2008.

All this would indicate that 16 years after the US and its allies put the Taliban to flight and in the process rooted out al Qaeda strongholds, the war effort is faltering.

Anthony Cordesman of the Centre for Strategic and International Studies in Washington says it is clear Afghan government forces are not capable of securing the country.

Unless US President Donald Trump adopts “a far more decisive approach”, security could collapse “either slowly and painfully over years or as a result of some shattering military defeat or critical power struggle at the top that divides security forces and the country,” he says.

President Donald Trump is proving to be something of a wildcard in deliberations about what to do in Afghanistan.

In the past week or so, he is reported to have reminded his advisers than in the vast sweep of history the great powers have failed to pacify Afghanistan – from Alexander the Great to the British Empire at its height.

He has a point.

But he is under pressure from his top security advisers, General James Mattis, the defence secretary and national security adviser H.R. McMaster, to reengage more purposefully in the Afghan conflict.

Both have Afghanistan experience. Mattis commanded the Marines in the early stages of the war, and subsequently led CENTCOM (Central Command), which is responsible for the Middle East.

McMaster spent two years in Afghanistan between 2010-12 overseeing a counterinsurgency effort that achieved some success.

Both have been deeply involved in a review of options in Afghanistan. They are in favour of a significant increase in American engagement, including making better use of the US military in forward positions with Afghan troops.

This, of course, risks casualties.

Trump has been a naysayer in the past, emphatically so.

In 2015 in a CNN interview, he described the Afghan war as a “terrible mistake”, but he conceded he would “begrudgingly” keep troops there.

“Are they going to be there for the next 200 years? At some point, what’s going on?” he asked. “It’s going to be a long time. We made a terrible mistake getting involved there in the first place … It’s a mess. And at this point, you probably have to because that thing collapse about two seconds after they leave.”

Trump is probably right, give or take a few days, or weeks, or even months. But for a president who will not want to be accused of “losing” Afghanistan, choices are limited.

He either ramps up America’s commitment in an effort to deal the Taliban a body blow, or he deploys a smaller number of troops to try to maintain a bloody status quo.

In the latter case, he will be told by Mattis and McMaster that America and its allies will continue to lose the war slowly.

This bring us back to Australia’s options.

Turnbull might remind himself that the last Australian to die in combat in Afghanistan was Corporal Cameron Bird VC. He was the 40th Australian to be killed in action.

The government needs to think very carefully before committing Australian forces to a role that goes beyond training and support. It should hasten slowly, and ask itself a simple question.

What would justify an Australian loss of life in a war that has gone on far too long, and been mismanaged from the start?

What should not be acceptable to Canberra is a mission in which Australian troops find themselves back in the sort of combat role they filled in Uruzgan province where a number were killed, including Corporal Cameron Bird, VC.