George Bush the Younger decided to finish the job his father had left half done and dispose of Saddam, not to mention find and destroy those famous weapons of mass destruction. Nothing better exposes the disingenuousness (or, at best, the confusion) of America’s motives in the past 25 years than the palpable disappointment of Bush and his administration—notably Vice President Dick Cheney—at not finding weapons of mass destruction. Iraq’s possession of chemical, biological, and nuclear weapons was supposed to be a bad thing, remember? If they had already been destroyed or never existed, then that was a good thing, right? Bush became so desperate to find weapons of mass destruction that, when a couple of suspicious mobile trailers turned up in northern Iraq, he announced he’d found some at last, though we soon learned that the trailers were for making hydrogen to inflate artillery balloons.

Bush’s eventual defense regarding the intelligence failures was basically “Look, everyone makes mistakes.” Which is perfectly true and perfectly reasonable, actually. But if the war was a mistake, even an innocent or well-intentioned mistake, any justification for staying on and on has disappeared as well. More than a decade later, why are we still there? Max Boot, writing in Time magazine, used the word “credibility” to explain why we had to stay somewhere we never should have gone. I thought that, after Vietnam, we had pretty much killed that notion. But no, it’s back.

And yes, the number of Americans in Iraq is relatively trivial, but President Obama has already agreed under pressure to increase troop levels, just long enough, you understand, to help wipe out the latest—and, seemingly, the worst—malefactor, the terrorist group known as ISIS.

ISIS is merely the most recent in a parade of horrible groups, Shiite and Sunni, religious and secular, murderous and even more murderous, to which we have been introduced through the years. They sometimes are our friends, though secretly helping the other side, or they are sworn enemies of the imperialist aggressor (that is, us), but still secretly taking bribes from the C.I.A. They are often splinters from some larger tree, either “brand extension” by the original group or its sworn enemy due to ideological or religious differences that are impossible to fathom.

Some members of these groups even come from the West. The news article about the child of middle-class immigrant strivers in a place like Cleveland or Liverpool who inexplicably withdraws from society and spends his days locked in his room reading the Koran and listening to rock music, only to emerge and resurface at some border crossing, trying to join a radical group that believes in, oh, I dunno, human sacrifice perhaps—news articles like that have become a cliché by now. “He was such a quiet, polite boy,” says a neighbor. “He used to write long love letters to Arianna Huffington and post them on Facebook.” (“Of course I remember him, darling,” says Arianna. “I had to hire two private guards to keep him away from me. But I gave him a blog anyhow. Why not?”)

Where did ISIS come from? What ever happened to the other Middle East groups we used to know? Where is al-Qaeda? How about the Taliban? Does anyone remember the mujahideen? If you do, you’re really showing your age. The mujahideen were the freedom fighters we armed and trained in order to drive the Soviets out of Afghanistan—a shrewd bank shot, everyone agreed, until, after the Soviets slunk away, we counted the leftover Stinger missiles in the freedom fighters’ broom closet and realized that many were now in the hands of unfriendly elements. And a lot of the mujahideen had gone with them.

It may be hard to believe, now that the media are all-ISIS-all-the-time, but the first reference to ISIS in any major news outlet—at least the first one referring to the now notorious terrorist group and not to Lord Grantham’s yellow Labrador, on Downton Abbey—was in the summer of 2013. This is not to criticize the media for being late to the party, or to suggest that the threat to Americans posed by ISIS is currently being exaggerated. It is merely to note that the number of analyses pouring out of Washington think tanks and experts available to CNN about who the heck these people are and what they want is pretty impressive, given that almost no one had heard of them a year ago. And it is also to note how fast the cast of characters in this drama can change, amid the anarchy we helped create—which is another reason not to leap to the assumption that anything further we might do would be of help.

Twenty-five years of this! And we were almost out of there when ISIS came along, through a door we opened to them in the first place.