The Wall Street Journal (WSJ) ran a troubling report on Wednesday describing how high-powered anti-tank guided missiles (ATGMs) are now in the hands of terrorist groups thanks to years of outside programs for arming various factions in Syria, including the Obama administration’s effort to arm “white hat” Syrian rebels.

As the Journal recalled, this is the program interventionists excoriated President Donald Trump for ending in 2017, but his concern about terrorist gangs gaining access to advanced weapons appear to have been well-founded. The threat of those weapons turning against American positions is one reason to reduce the American footprint in Syria.

It is not just American-made weapons vanishing into the Syrian quagmire. All of the regional and world powers that tossed weapons into the fighting pits of the Syrian civil war have reason to worry about those weapons coming back to haunt them:

A U.S. program begun in mid-2013 provided weapons including ATGM missiles to rebels fighting the Assad regime in Syria. President Trump later canceled the program, saying in a 2017 interview with The Wall Street Journal that it allowed weapons to fall into al Qaeda hands. “There is absolutely the possibility that the U.S. may face some of the same ATGMs it has delivered in the past to the Middle East,” said Omar Lamrani, a senior military analyst with the Austin, Texas-based defense-intelligence firm Stratfor. Islamic State and al Qaeda offshoots, among others, now possess American-made missiles, he added. Those and other nonstate actors in the Middle East also have antitank missiles—some of them based on U.S. designs—manufactured in Bulgaria, China, France, Iran and Russia, according to analysts who track weapons proliferation.

As the article explained, guided anti-tank missiles are far more dangerous than the ubiquitous rocket-propelled grenades and roadside bombs. Reports suggest the Islamic State, the Taliban, and Hezbollah possess missiles they can launch from over a mile away and that can punch through a thousand millimeters of armor. Enterprising militia fighters have found ways to use the missiles against targets other than tanks, such as taking out grounded military helicopters and attacking entrenched infantry positions.

Defending against these weapons is difficult because fighting vehicles cannot be armored enough to withstand them or made agile enough to evade them. The WSJ reported that the U.S. is developing active defense systems (in other words, shooting down incoming missiles) but has fallen behind, in part due to “the Army’s complex acquisition system.” The new Chairman of the Joint Chiefs of Staff, Gen. Mark Milley, has indicated streamlining these systems will be a high priority.

The Syrian military has long complained about rebel groups using American-made anti-tank missiles, especially the TOW missile. Some experts believe U.S. allies like Saudi Arabia and Turkey have allowed these weapons to pass into Syria. The Islamic State seized others after it stormed into Iraq and established the southern half of its “caliphate.”

Absent Russia’s intervention on behalf of the Assad regime, the missiles might even have worked to halt Syrian military advances over the past few years, as rebel fighters were able to pull off a few “tank massacres” when faced by large formations of Syrian armored vehicles.

The Obama administration was eager to arm the Free Syrian Army (FSA) rebel faction until the end of 2015 when Russian intervention began turning the tide of the civil war and U.S. attention shifted to the Kurdish-led Syrian Democratic Forces (SDF) and their battle against the Islamic State. The Free Syrian Army is aligned more strongly with Turkey these days and has assisted with Turkey’s military campaign against the Kurds. Quite a few FSA flags were unfurled on New Year’s Eve in Istanbul, to the consternation of Turks who think their Syrian allies might be excessively optimistic about Turkey’s willingness to overthrow Assad.

The European Parliament warned in November that its member states “systematically failed to apply” European Union (EU) rules for arms sales abroad and said it was particularly “shocked at the amount of EU-made weapons and ammunition found in the hands of Da’esh (ISIS) in Syria and Iraq.”

The European Parliament blamed the United States and Saudi Arabia for passing too many weapons to groups opposing Syrian dictator Bashar Assad.

“Supplies of material into the Syrian conflict from foreign parties – notably the United States and Saudi Arabia – have indirectly allowed ISIS to obtain substantial quantities of anti-armor ammunition,” the EU charged.

The Brookings Institution argued in a 2016 analysis of the FSA that support for the highly decentralized rebel group during the Obama years was too timid at first, then too lavish as the administration sought white-hat allies it could support to avoid charges that it was not doing anything about the Syrian disaster.

Perhaps a more energetic effort in the early years of the civil war might have whipped the FSA into shape as a fighting force that could defeat Assad without a long and grinding stalemate that inflicted endless horror on the civilian population, but it is difficult to imagine the Obama team supporting such an effort just a few years after riding into office as critics of the Iraq war, and it would have been a very tough sell to the American people.

What we got instead was a strategy of supporting rebel groups with dubious affiliations and insufficient discipline to control their supply of weapons. Syrian groups desperately trying to overthrow Assad did not want to expend their strength, expose their flanks, and weaken another enemy of Assad by fighting ISIS. Those opposed to ISIS, like the Kurds, were not enthusiastic about regime change and concluded it was unlikely after the Russian intervention.

The results of this confused fumbling in Syria, where the “smart set” once thought the ideal strategy was giving all of the unpleasant combatants weapons so they could kill each other, include regional destabilization, refugees destabilizing Europe, humanitarian horror, growing spheres of influence for Russia and Iran, and advanced anti-tank missiles added to the arsenal of terrorism.