President Barack Obama made an interesting change to the criteria for victory in Afghanistan during his State of the Union speech -- namely that al Qaeda has been "degraded."

It's easy to see why: No U.S. president likes to withdraw troops from a 10-year war without declaring "mission accomplished." Still, there's something worrying in this claim about al Qaeda.

Among terrorism experts there has been a lively debate for the past year over whether al Qaeda is now defeated. The group suffered huge double blows with the "Sunni Awakening" in Iraq, where Sunni militias turned on al Qaeda, and the killing of Osama bin Laden in 2011. Drone attacks, however ethically questionable, have since killed many of the group's other leaders.

Most important, the global al-Qaeda brand has been badly damaged by the death and destruction that the group's adherents visited on fellow Muslims. None of the protests of the Arab Spring, the most important event in the Middle East in decades, were inspired by al Qaeda or terrorism.

So yes, al Qaeda has been degraded. But what does this signify? Al Qaeda was always as much an organizing and funding principle as a military-style organization. That's why the damage to the brand is more important than drone strikes on its leaders. This nature makes al Qaeda fluid and opportunistic. Marginalized in Iraq, al-Qaeda fighters there have now moved across the border to Syria, morphing into al Qaeda-inspired militias such as the al-Nusra Front.

Al-Nusra learned from the mistakes made in Iraq. The group earned support from ordinary Syrians by not randomly slaughtering fellow Sunnis, and by doing a better job than the Free Syrian Army of providing food and corruption-free services to civilians behind the rebel lines. No doubt this will change, but when the U.S. listed al-Nusra as a terrorist organization last year, Syrians turned out in the streets to protest the move.

Similarly, al Qaeda in the Islamic Maghreb saw an opportunity in Mali, once Muammar Qadaffi was deposed in Libya. Libya's weapons depots and borders were left unprotected, giving Tuareg and al Qaeda in the Islamic Maghreb fighters in Libya an open desert highway to bring their fight to Mali. The threat that they were about to capture the Malian capital Bamako, and create a new 1990s Afghanistan in Saharan Africa, triggered French intervention.

So yes, Obama was accurate. But the militant Islamism that the group represents shows such obvious regenerative and mutational qualities that it probably isn't smart to take its degradation as a measure of victory.

U.S. force has denied al Qaeda its organizational space in Afghanistan, but recruiting goes on elsewhere. When U.S. troops leave, we don't yet know what will happen. We'll know al Qaeda has been sufficiently degraded to declare victory in Afghanistan if they don't return with the Taliban after U.S. troops leave, if the Al-Nusra Front can be marginalized in Syria, and if al Qaeda's adherents in North Africa can be kept on the run. 

(Marc Champion is a member of Bloomberg View's editorial board. Follow him on Twitter.)