We have been told by experts, counterterror analysts, and academicians alike that al-Qaeda and the Islamic State in Iraq and Syria are entirely distinct entities. Not only do they not cooperate, but they are adversarial. Al-Qaeda’s affiliate in Syria, The Nusra Front, and ISIS regularly engaged in combat. Even when the two terrorist organizations began to coordinate with each other in September, most still believed that ISIS and al-Qaeda were incompatible.

Well, maybe that’s not the case.

“The terrorist attacks in Paris were nightmarish in many ways, but perhaps the most worrisome news to come out of the Charlie Hebdo affair is that followers of a ‘pure’ al Qaeda affiliate – al Qaeda on the Arabian Peninsula – and of ISIS – the Islamic State of Iraq and Syria – worked together,” The Weekly Standard’s Thomas Donnelly reported on Monday.

Video first obtained by the SITE jihadist monitoring group, analyzed by Thomas Jocelyn at Long War Journal and even reported by the New York Times reveals Paris gunman Amedy Coulibaly swearing his loyalty to ISIS. “I pledged allegiance to the caliph [ISIS leader Abu Bakr al-Baghdadi] as soon as the caliphate was declared,” said Coulibaly. It’s also notable that Coulibaly’s girlfriend and accomplice, Hayat Boumeddienne, escaped from France to Turkey and then to Syria – and presumably ISIS protection – just prior to the attacks.

That makes the Paris attacks something akin to an ISIS-al Qaeda combined operation. The other two Paris attackers, Cherif and Said Kouachi, professed to be trained and funded by the Yemen-based AQAP, had been interviewed by Anwar al-Awlaki – the group’s charismatic American-born propagandist killed in a controversial drone strike in 2011 – and, while in Yemen, had befriended Umar Farouk Abdulmutallab, the “Underwear Bomber” who attempted to blow up a Christmas Day airline flight to Detroit in 2009.

On Monday, reporters confirmed that the two brothers who executed the attack on Charlie Hebdo were directly linked to a well-known al-Qaeda recruiter in Europe. At the very least, this scuttles the narrative that these two attackers were “self-radicalized lone wolves” who merely stumbled across a French language issue of Inspire and were driven to murder.

The degree to which ISIS and AQAP coordinated ahead of this attack, if at all, may never be known. It may also be irrelevant, wrote international affairs analyst Bobby Ghosh in Quartz. “[T]he real lesson from Paris is that the distinctions between Al Qaeda and ISIL are immaterial to self-styled jihadis,” he wrote.

If there’s a difference between Al Qaeda and ISIL, it was lost on these men. The brothers Kouachi attacked Charlie Hebdo because of its cartoons depicting the prophet Mohammed. Coulibaly said he was motivated by France’s role in the war against ISIL. But their allegiances and affiliations didn’t prevent them from working together, from killing together.

The two groups share a nihilistic worldview, a loathing for modernity, and for the West. They subscribe to the same perverted interpretations of Islam. Other common traits include a penchant for suicide attacks, and sophisticated exploitation of the internet and social media. Like ISIL, several Al Qaeda franchises are interested in taking and holding territory; AQAP has been much less successful at it.

The feud between these two terror groups is over personnel, resources, and prestige. While these are issues that excite organizational partisans, they are less relevant to the aspiring Western jihadi.

Between al-Qaeda, Ansar al-Sharia, Boko Haram, ISIS, Abu Sayyaf, Jemaah Islamiah, and others, perhaps the West should be more concerned about the common ideology that animates these groups and their members. It is important to be aware of the arcane issues which divide these groups so they can be exploited, but, for those who wish to kill Westerners in the name of Islam, these organizations are interchangeable and of relatively equal value.