To put it another way, the justice of war can change as the strategy does. Those big questions about whether the right cause can be pursued at the appropriate cost apply not just at the start of a war, but for its duration. This has surprising effects when you think through the course of the war in Iraq. As the conflict entered its bloodiest, most sectarian phase—from roughly 2006 on through the Surge—Americans came to believe that the use of force in Iraq was wrong, according to Pew. (A plurality has, for the most part, continued to believe that ever since.) Paradoxically, at that time, the intervention may have had a stronger case than when the war began.
McMahan explained: “There was more of a case for an American occupation of Iraq after the United States had effectively destroyed any kind of security institutions there and had disbanded the army and kicked the Sunnis out of power. It left a real vacuum in the kind of political, social, and security institutions in the country. Somebody had to do something about that to protect people from predators and to protect people from violence from the other sects within the country.”
The bull had destroyed the china shop. Yet only the bull could fix it. More than that, argues the ethicist Gerard Powers, it would have been wrong for the United States to withdraw at that point. One might say, looking at the situation now, “Let Iraq and Syria be torn apart by their ancient hatreds. But that would be shirking our moral obligation, because the United States became, voluntarily, very much a part of those ancient hatreds. So I think the argument leads to a strong sense of moral responsibility to do something to address the problem.” As McMahan pointed out, it would have been better for the United States to pay for neutral peacekeepers, but that was never a realistic possibility.
There is no redemption at the end of this kind of continuously applied moral theory; it ends, hopefully, with simply the fewest number of civilians killed needlessly. But there is a constant chance to do better, to pay for one’s past mistakes. America, as a democracy with a military obsessed with its own failures, is better suited than most countries to take those chances. It can change course midstream and improve upon its moral failures. By contrast, once Russia intervened in Ukraine or Syria, the moral course of those wars was set. There is no chance that war-weary Russians will vote out their president, in the way that Americans chose pro-withdrawal Barack Obama over the hawkish Hillary Clinton and John McCain in 2008.
But with those chances to do better come chances to renew the chaos and injustice. Just look at Afghanistan. An initial cause that could hardly be more just—defending against further terror attacks and bringing the attackers to justice—seems to have little to do with the mission Americans and their allies are still fighting nearly two decades later. The questions that this raises about the larger goals Americans are fighting for aren’t only debates about strategy—they’re also tied to judgments about whether the cause is even a just one any more.