What have we learnt from Afghanistan?

The 20-year-long conflict, which was bookended by two intelligence failures of almost unprecedented magnitude, has cost the US, Australia, and the other members of the coalition more than a trillion dollars and 3500 lives.

Hundreds of thousands of Afghans, many of them non combatants caught in the crossfire of a war without end, have also been killed. Millions have been displaced and whole communities have been destroyed.

And for what? It is just under two decades since the allies went into the poverty-stricken country, famous as the "graveyard of empires", to overthrow the Taliban, wipe out al-Qaeda's terrorist bases and, in the colourful words of President Biden, to bring Osama Bin Laden to "the gates of hell".

While, for a space, the Taliban was beaten back and a form of democracy established, the gains were temporary. As of Monday the Taliban is back in charge, stronger and even better equipped than ever; the country's president has fled, and coalition forces are scrambling to retain control of Hamid Karzai Airport three kilometres from the centre of Kabul.

The airport, the last Western-held bridgehead, is the only hope for tens of thousands of Afghans now marked for torture and, in many cases, almost certain death because they worked with US, Australian and other coalition forces.

The Morrison government has shrugged off criticism of its failure to get the people who facilitated the work of our troops, diplomats and aid workers out for months. Although it has had years to prepare for this moment, it proved incapable of doing the job.

While the PM was patting himself and his government on the back on Monday for having rescued 450, it stands to reason, given the duration of the mission and the scope of our involvement, thousands more remain.

With conditions on the ground deteriorating rapidly, and the risk of open warfare between the Western forces and the Taliban, there are no guarantees the planned mercy mission to evacuate Australians and some locals will even take place.

An unknown number of men, women and children are about to pay a terrible price for this government's bureaucratic procrastination and complacency.

Afghanistan, a country with a long and tragic history, is now the setting for a horrific drama as old as time. Although the Taliban has tried to portray itself as less militant and fanatical, and capable of running a modern nation state, there is no reason to believe this leopard has changed its spots.

While the flight of the President and the collapse of the military has spared Kabul from becoming a 21st-century Stalingrad, it is only a matter of time before the revenge killings, the stonings, the beheadings, the betrayal of neighbours by neighbours, of friends by friends, and of kin by kin begins in earnest.

Millions of Afghans, especially the women and girls who have experienced a very brief spring of liberty, now fear a new holocaust - and with good reason.

So, was it worth it? Lieutenant-General Peter Leahy, the chief of the army from 2002 to 2008, has said if governments learn from this debacle and don't make the same mistakes again, the answer is yes.

Sadly, if past actions are an indication of future performance, that is extremely unlikely.

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