Peace, if it ever exists, will not be based on the fear of war, but on the love of peace.
It will not be the abstaining from an act, but the coming of a state of mind”
Herman Wouk, The Winds of War

The US war in Afghanistan has failed. Vietnam failed. Iran is the biggest winner out of the Iraq war. What are the lessons here? Why does the United States have such an agonizing time learning them?

A town hall has erupted across the American commentariat. The faultline is an understanding of the strategic difference, and moral consequences, between wars of nation-building versus wars that punish aggression and promote security and peace.

When war moves beyond the redress of the initial aggression, and invasion becomes the bridgehead for building a democracy in America’s image, the terrain can turn fatally hostile, and defeat can follow.

The verdict on Afghanistan is in. As Jon Soppel of the BBC said, “America’s attempt to export liberal democracy to Afghanistan is well and truly over. America’s effort to build a civil society in Kabul and beyond — also in tatters.”

When war moves beyond the redress of the initial aggression, and invasion becomes the bridgehead for building a democracy in America’s image, the terrain can turn fatally hostile, and defeat can follow.

This was the lesson of Vietnam with the South’s collapse in 1975. This was popularized in the famous “Powell Doctrine,” named for its author, General Colin Powell, who would later become Chairman of the Joint Chiefs under President George H.W. Bush, and then Secretary of State under President George W. Bush.

The Powell Doctrine consists of 8 key questions, which all required answers in the affirmative for a clear decision to wage war.

“Is a vital national security interest threatened? Do we have a clear attainable objective? Have the risks and costs been fully and frankly analyzed? Have all other nonviolent policy means been fully exhausted? Is there a plausible exit strategy to avoid endless entanglement? Have the consequences of our action been fully considered? Is the action supported by the American people? Do we have genuine broad international support?”

Vietnam failed the test. But the lessons of Vietnam were learned and stuck for the next war, the 1991 liberation of Kuwait, which coincided with the George HW Bush-Powell command. The world was affronted by Iraq’s naked aggression, in violation of international law. Bush mobilized a global coalition to reverse it – successfully. Most critically, Bush and Powell rejected the option of taking the battle back to its source and removing Saddam.

But by 9/11, the lessons were forgotten. It was absolutely right to avenge the terrorist attacks from Bin Laden and Al Qaida against the United States. Nearly 3000 people from across the globe were killed. The world stood with the United States. The calling card had an incontrovertible return address.

The Taliban were overthrown, and Al Qaida was taken down, but neither were eviscerated. Bin Laden ultimately faced justice 10 years later.

But the George W Bush-Dick Cheney-Donald Rumsfeld entente was obsessed with Iraq and their belief that Saddam was directly tied to 9/11 and armed with weapons of mass destruction. (Historians may well judge that decision to go to war against Iraq as marking the moment of American imperial over-reach and the trigger of America’s permanent decline.)

We could tell who the victor was in Iraq through video of arriving dignitaries at Baghdad International. The Americans would deplane with bulletproof vests. The Iranian president would descend in a business suit.

The Iraq war distracted and obstructed the proper—and early – conclusion and exit from Afghanistan. It went from eliminating terrorism to something far grander: Afghanistan as the new model for democracy in the developing world. The United States, as Bush outlined in his second inaugural, was a beacon of freedom around the world.

But as Biden reminded Americans in his address this week, “Our mission in Afghanistan was never supposed to have been nation-building . . . Our only vital national interest in Afghanistan remains today what it has always been: preventing a terrorist attack on the American homeland.”

The costs of failing a major war for nation-building are enormous – endless – for the United States. As Biden said during the 2020 campaign, “The idea of us being able to use our armed forces to solve every single internal problem that exists in the world is just not within our capacity. The question is, is America’s vital self-interest at stake or the self-interest of one of our allies at stake?”

Second, the image and standing of the United States suffers – and in 2021, right at the moment when the Western allies are pleased to have Biden and the US back in a leadership position, they are immensely concerned that America’s staying power is wanting. How long does this moment last? What if Trump or Trumpism comes back in 2024?

The lesson may be not to fight wars to impose democracy from the outside, but to leverage it from the outside with those on the inside who want it.

And allies, who have been so loyal and sacrificed so much, feel taken along for the ride. There is real anger, with the US wearing the blame. Angela Merkel: “This is an absolutely bitter development: Bitter, dramatic and awful, especially for the people in Afghanistan.” The recriminations here in Australia among veterans who wonder if it was worth it, and from so many who care for the fate especially of Afghan women and girls, and the Afghans who worked with the Aussies, are searing. Will sentiment that America takes Australia for granted become more prevalent after the fall of Kabul?

Third, if America is weaker, its adversaries – Russia, China and Iran – are relatively stronger, and can make mischief with a freer hand. Secretary of State Tony Blinken said, as Kabul fell, “By the way, from the perspective of our strategic competitors around the world, there’s nothing they would like more than to see us in Afghanistan for another five, 10, 20 years. It’s simply not in the national interest.”

What does it take to learn these lessons and apply them consistently over decades? Leadership, obviously – but even leaders who we may admire today are uneven. Biden himself voted in 2003 for the Iraq war. And Powell knew his doctrine did not work for war with Iraq but did not resign from Bush’s Cabinet in protest.

Sometimes, calamity occurs by fate. In 2000 the Bush-Gore presidential election, with the ugly mess of vote-counting in Florida, was decided by one vote in the US Supreme Court. What if the court had ruled 5-4 for Gore? 9/11 likely could not have been stopped; the intelligence community missed the plot. Gore would have responded as Bush did – but almost surely would not have expanded the conflict to Iraq. So the defeat of the Taliban and execution of bin Laden could well have been done in Gore’s first term. It would have been a win on par with Bush’s father in Kuwait. Imagine: US leadership across the partisan divide.

The lesson may be not to fight wars to impose democracy from the outside, but to leverage it from the outside with those on the inside who want it. For those who pose existential threats of terror, mass destruction, genocide and naked aggression: meet force with force. But that means you can’t – you won’t – save all who need to be saved from tyranny, oppression, and atrocity.

Neither the Powell Doctrine nor the aftermath of Afghanistan provide the bright line that will help decide whether to commit to the next war. If China moves to invade and occupy Taiwan, is that the equivalent of the Soviets crushing Czechoslovakia in 1968? Or is it Saddam seizing Kuwait in 1990? And when we decide what it is, what do we do?

At the least, we must know what we are fighting for, and what victory looks like, and what defeat feels like. And what not to fight for.

Can our countries think through and our leaders absorb these lessons?