The 20th anniversary of the 9/11 attacks raised two questions. First, what we have learned? And second, where do we go from here?
In my view, we, the Western democracies, have learned to take international terrorism seriously and worked out how better to guard against it. Invading Afghanistan, assassinating Osama Bin Laden (and numerous other jihadist fighters), bombing Isis in Iraq and Syria, and detaining hundreds of suspects at Guantanamo and 'black sites' were extreme and controversial responses. Some would say they were counterproductive.
While they did not eliminate all terrorists, these military initiatives appear to have kept terrorist organisations on the defensive and reduced the incidence of terrorist attacks in Europe and America.
Most recent attacks have been perpetrated by domestically based radicalised individuals, or deranged persons, rather than by known cells of international conspirators.
Stringent inspections of public transportation passengers have cut airline bombings and hijackings to nearly zero. Governments have expanded photographic, electronic, and human surveillance policies.
While hard to evaluate, given official secrecy rules, authorities claim to have detected and foiled numerous terrorist plots.
Statistics suggest the steady reduction of jihadist terrorist-related fatalities in Western countries. No attack remotely near the scale of 9/11 has recurred in the US and only one
attack is attributed to a foreign jihadist organisation, as opposed to intermittent one-off lone-wolf shootings.
The costs have been considerable. In addition to the dollar costs to governments and corporations of employing ranks of new security specialists and frontline guards and purchasing surveillance devices, the public has suffered reductions of civil liberties and privacy. Passengers and consumers have faced delays and indignities.
The war on terrorism can no more be won than the wars on crime, drugs, poverty, intolerance, disinformation…or Covid-19.
Nevertheless, most officials, business leaders, and publics have grudgingly accepted the costs and inconvenience as the price to pay for greater security. Few are clamouring for a return of the casual pre-9/11 security precautions.
And now? Ironically the return of the Taliban, a militarised ideological movement now governing 40 million Afghans, coincided with the 20th anniversary of the 9/11 attack which precipitated the US entry into Afghanistan.
Holding the Taliban leaders to their promises of amnesty, tolerance, emigration, and above all of suppression of international terrorist organisations, is the challenge facing Western governments.
The Taliban need food, finance, expertise, and legitimacy from the West. China, Russian, and Pakistan will intervene, but this will not be enough.
Western leaders, UN agencies and NGOs must work with the Taliban for the welfare of the Afghan people.
Western satellite intelligence and precision drone strikes may be needed to suppress Al Qaeda and Isis-K cells gathering in remote parts of Afghanistan. Foreign forces operating in Afghan airspace will require permission from ministers of the new Islamic Emirate in Kabul who are also wanted terrorists. Western pragmatism and compromise will be necessary.
And the future? It will look like the recent past. Successful counter-terrorism policies will be strengthened and refined. Terrorist attacks will occur, but only intermittently and perpetrated unpredictably by individuals, more often motivated by white supremacist bigotry than by religious extremism. Damage control and injury mitigation policies will parallel prevention policies.
Government preparedness, and public surveillance, will intensify, but within tolerable limits set by law and economy.
Looking ahead, President Joe Biden in his first post-Afghanistan speech hinted at a reduced US commitment to world-wide "national building".
The US entered periods of caution after the "loss" of South Vietnam in 1975 and the failure of regime change in Somalia in 1993 (the "Blackhawk Down" disaster).
President Carter's and President Clinton's hesitancy to act abroad against atrocities allowed the Shia theocrats to seize power (and US hostages) in Iran in 1979 and the Rwanda Hutu massacre of Tutsis to run its deadly course in 1994.
What is needed is not less US intervention but more carefully crafted US intervention abroad. Biden should not shut down overseas military commitments indiscriminately, as Trump began to do, but rather to focus them parsimoniously on achievable goals, notably counter-terrorism. At the same time, minimising risk to innocent people and working with partners and host authorities should be prioritised.
The "war on terrorism" can no more be won than the "wars" on crime, drugs, poverty, intolerance, disinformation…or Covid-19.
But these campaigns of mitigation should be administered with discrimination and skill, like medicine, to minimise their dire side-effects. In this endeavour, the US can still play a leading role, but it must work with willing partners, and work more skilfully.
This is what we have learned from 9/11 and what should guide our policies in the next 20 years.
• Stephen Hoadley is Associate Professor of Politics and International Relations at the University of Auckland.