When President Obama announced US airstrikes in Iraq, most observers understood that the US would be bombing members of ISIS. What many did not know was that, in a twist of such bitterly symbolic irony that it could only occur in the Middle East, the US would also be bombing hundreds of millions of dollars worth of American military equipment.

Here's why: in the decade since the 2003 US-led Iraq invasion, the US has spent a fortune training and arming the Iraqi army in the hopes of readying it to secure the country once America left. That meant arming the Iraqi army with high-tech and extremely expensive American-made guns, tanks, jeeps, artillery, and more.

we're bombing the guns that we didn't mean to give ISIS because we didn't give guns to their enemies because then ISIS might get guns

But the Iraqi army has been largely a failure. When ISIS invaded northern Iraq from Syria in June, the Iraqi forces deserted or retreated en masse. Many of them abandoned their American equipment. ISIS scooped it up themselves and are now using it to rampage across Iraq, seizing whole cities, terrorizing minorities, and finally pushing into even once-secure Kurdish territory. All with shiny American military equipment.

So the US air strikes against ISIS are in part to destroy US military equipment, such as the artillery ISIS has been using against Kurdish forces.

The absurdity runs deep: America is using American military equipment to bomb other pieces of American military equipment halfway around the world. The reason the American military equipment got there in the first place was because, in 2003, the US had to use its military to rebuild the Iraqi army, which it just finished destroying with the American military. The American weapons the US gave the Iraqi army totally failed at making Iraq secure and have become tools of terror used by an offshoot of al-Qaeda to terrorize the Iraqis that the US supposedly liberated a decade ago. And so now the US has to use American weaponry to destroy the American weaponry it gave Iraqis to make Iraqis safer, in order to make Iraqis safer.

It keeps going: the US is intervening on behalf of Iraqi Kurds, our ally, because their military has old Russian-made weapons, whereas ISIS, which is America's enemy, has higher-quality American weapons. "[Kurdish forces] are literally outgunned by an ISIS that is fighting with hundreds of millions of dollars of U.S. military equipment seized from the Iraqi Army who abandoned it," Ali Khedery, a former American official in Iraq, told the New York Times.

More: One reason that ISIS has been so successful at conquering northern Iraq is that it has a huge base of operations in Syria, where it had exploited the civil war to overtake huge swathes of Syrian territory. One reason that ISIS was so successful in Syria is that the US refused to arm moderate Syrian rebels, for fear that the weapons would fall into ISIS's hands. So that made it easier for ISIS to overpower the under-funded moderate rebels, and now ISIS has seized, in Iraq, much better versions of the weapons that we were so worried they might acquire in Syria. So now we're bombing the guns that we didn't mean to give ISIS because we didn't give guns to their enemies because then ISIS might get guns.

It's not just ironic; it's a symbol of how disastrous the last 15 years of US Iraq policy have been, how circuitous and self-perpetuating the violence, that we are now bombing our own guns. Welcome to American grand strategy in the Middle East.