Speaking to reporters recently, Pentagon spokesman Rear Adm. John Kirby noted that the five-month-old campaign against the Islamic State in Iraq and Syria is progressing, and coalition forces are enjoying several notable successes.

“We’ve had a dramatic effect on their ability to get revenue from oil,” Kirby asserted.

“We know we’ve destroyed hundreds and hundreds of vehicles, artillery positions, checkpoints,” he continued. “We know that we’ve killed hundreds of their forces, and we know simply by virtue of where they are on the map and how little they are moving now that we have blunted the momentum that they once enjoyed.”

This is no boast. The Islamic State’s advances toward the Turkish border in Syria and Baghdad in Iraq have been checked. While the group is not giving up much territory, it is also failing to acquire more through offensive operations.

As for just how much credit the Pentagon deserves for this condition, that point is arguable.

A report in The Atlantic observed that ISIS’s momentum largely stalled after a spectacular summer offensive primarily as a result of the Islamic State leadership’s decision to turn on the members of its own military coalition; namely former Ba’athists and the “disaffected Sunni elite.”

But once its initial gains were secured, ISIS quickly betrayed the very groups that had aided its advance. Most prominently, ISIS declared the reestablishment of the caliphate, with the group’s spokesman Abu Muhammad al-Adnani claiming that “the legality of all emirates, groups, states, and organizations, becomes null by the expansion of the khilafah’s authority.” The statement clearly signaled that ISIS believed it had usurped the authority of its allies; indeed, in early July it rounded up ex-Baathist leaders in Mosul (doing so proved particularly problematic for ISIS because the ex-Baathists were also managing the actual governance and administration of the northern Iraqi city, and their arrest hastened the rapid disintegration of basic services).

The Atlantic’s Daveed Gartenstein-Ross also remarked on the fact that the Islamic State committed a similar strategic blunder when their actions forced Kurdish indigenous defense forces to engage ISIS:

ISIS committed a more damaging error at the beginning of August, when it launched a surprise incursion into Iraq’s Kurdish territory and promptly engaged in a campaign of genocidal slaughter and enslavement against the Yazidi minority sect. The moves were pointless from a military perspective, since the Kurdistan Regional Government’s Peshmerga forces weren’t fighting ISIS and the Yazidis didn’t pose a threat to the incipient caliphate. These decisions, along with the beheading of the American journalists James Foley and Steven Sotloff, helped draw even more enemies into the theater, including the United States and an international coalition backing U.S. military action.

Furthermore, as CNN reported, while ISIS’s blitz across Iraq may be halted for now, “there are many caveats” to the claim that the group has been defanged.

A U.S. intelligence official tells CNN that ISIS’ “core capabilities remain fundamentally unchanged.”

The official notes that while the group has suffered battlefield losses, it’s mainly mid-level fighters and “it’s likely most have been replaced.”

Additionally, the group is still using a huge safe haven area in Syria “from which to train, plan and conduct attacks. The group can freely funnel men and material between Iraq and Syria.”

And, the official added, “It’s the wealthiest terrorist group in the history of terrorism. They’ve got hundreds of millions of dollars, plenty of recruits and a slick propaganda machine that continues to generate more of both.”

While it is debatable as to how much credit the Pentagon and America’s coalition partners are due for the forestalling of the ISIS advance, it is for the most part true that the Islamic State’s expansion has been halted. That condition is likely to persist for the rest of the winter. Whether it lasts through the spring offensive season is the true test.