When ISIL recaptured the ancient city of Palmyra on December 11, the Syrian regime and Russia were in the middle of a vicious assault to retake the eastern parts of Aleppo from the rebels. The diversion of regime resources left an opening for the militants to roll back into the city after they lost it in March.

The loss of Palmyra happened despite a serious attempt by Russia to prevent it, and showed the regime was unable to defend all of its fronts as it sought to fortify critical strongholds in Aleppo, Homs and Damascus.

The recapture of Palmyra on Thursday, as with its loss in December, exposes the regime’s vulnerabilities. Damascus has Russia, Iran, Hizbollah and the United States to thank for the defeat of ISIL in Palmyra. The regime forces could not have done it on their own and the Russian air force may not have been able to expel the militants without the near complete destruction of the city.

But there is something more telling about the recapture of Palmyra. The contribution of the US air force to the fight is a notable turn of events. In December, Lt Gen Stephen Townsend, commander of the anti-ISIL coalition, told reporters in Baghdad that the US would step in to strike against ISIL in Palmyra “if the Russians and the regime don’t strike it”.

“We’re just kind of staying out of it and watching it right now, and protecting our own interest, and letting the Russians sort that out, which I think is probably the common sense way to go about Palmyra,” he said.

The US did not stay out of it, however. It carried out dozens of air strikes against ISIL even though Russia and the regime did too. Regardless of whether the participation suggests a policy shift, the move points to a subtle change in the American behaviour in Syria. This change of attitude involves complete disregard for the conflict’s sensitivities.

American officials involved in the fight against ISIL no longer seem interested in dealing with the political context of its operations in Syria. A de facto alliance with Iran, Hizbollah and Russia against ISIL in Palmyra would have been more eyebrow-raising a year ago. Today it is a passing event.

This was not an isolated incident. The US has also insisted that Kurdish militias will spearhead the fight against ISIL in Raqqa. In arguing the case, officials seem to focus on Turkey’s objection to the Kurdish role, as if that is the only flaw in the decision. The primary concern for the lead role of Kurdish militias is local perception of these forces. It is what makes those battling ISIL “liberating” versus “occupying” forces.

Gen Townsend dismissed the concern over how these militias are perceived locally by stating the fighters are from the wider Raqqa province. The statement suggests that the YPG, the Kurdish People’s Protection Units, are Raqqa locals, because the wider province of Raqqa includes Kurds. This ignores how people in Raqqa, and elsewhere, view the YPG militias and distinguish them from the Kurdish people in general.

The statement also appears to avoid dealing with the question of keeping out militias viewed suspiciously by locals, a logic the US pushed for in Mosul. Gen Townsend’s remarks could indeed be a response to a statement by the Turkish prime minister that called on the US to follow the same logic it itself championed in Mosul in Raqqa.

Another example of the disconnect is the move by the US-backed forces in Manbij on Thursday to hand over some areas under their control to the Syrian regime as a way to create a buffer zone between them and the Turkish-backed rebel forces fighting ISIL in eastern Aleppo. If the prospective role of the Kurdish-led militias in Raqqa was a bad idea, this move made it even worse. It has ensured that many more will see these forces as regime allies. Worse, the same US-backed forces allowed “humanitarian” convoys to enter the city of Manbij, which was liberated from ISIL in August. According to Pentagon spokesman Captain Jeff Davis, the convoys included “some armoured equipment”.

For any Syrian opposed to the regime, these developments in Palmyra, Manbij and Raqqa point to an unsavoury US policy. After nearly two and a half years in Syria, American officials may have lost sight of such sensitivities but they should not.

The regime’s ability to secure even the 35 per cent of territory under its control is limited. It is incapable of fighting on several fronts without risking the loss of territory, as happened in December in Palmyra. It is also incapable of securing its supposedly safe areas, as demonstrated by the sophisticated operation that Al Qaeda carried out in Homs last Saturday, in which five militants infiltrated two well-guarded neighbourhoods, stormed intelligence compounds and shot dead a high-ranking official and around 40 other security cadres.

The regime’s limitations mean proper investment in other forces to fight extremism elsewhere inSyria should be a priority for the US, if it wants to defeat extremists and keep them defeated. No matter where the US stands on the question of the regime’s legitimacy, it should understand that the regime is incapable of fighting extremism in the whole of Syria. And in order to invest in other forces to fill the vacuum, it has to stay focused on how its policy is perceived.

Unfortunately, the US seems to be developing more dangerous blind spots in Syria. This unawareness, or disregard, of the political context in which it operates will undoubtedly come back to haunt it in the future.

Hassan Hassan is a senior fellow at the Tahrir Institute for Middle East Policy and co-author of ISIS: Inside the Army of Terror

On Twitter: @hxhassan