Part of the series "Ten Lessons Since the 9/11 Attacks," in which CFR fellows identify the top threats and responses going forward. Read more in the series.
By the measure that matters most, U.S. efforts since 9/11 to prevent nuclear terrorism have been a resounding success: There has been no nuclear terrorist attack. Chalk that up to four factors--the last of which should be a warning against declaring victory just yet.
The invasion of Afghanistan is not usually thought of as part of U.S. efforts to prevent nuclear terrorism, but it should be. A terrorist attack using nuclear weapons would likely be complex, requiring specialists in a host of different areas and substantial time to prepare. Executing such a mission without severely risking operational security requires the sort of robust sanctuary Afghanistan provided before NATO went in.
U.S. security against nuclear terrorism also got a massive boost from cooperative efforts to secure nuclear weapons materials around the world. In the months prior to 9/11, many in Congress were fighting to slash spending on this most powerful tool in the U.S. security arsenal. That stance was quickly reversed, and in the ensuing years U.S. programs were supplemented with efforts from a host of international and nongovernmental partners. Security for highly enriched uranium and weapons-grade plutonium is better today as a result.
Traditional counterterrorism and homeland security also made an important contribution. Analysts often argue that the only difficult part of a nuclear terrorist plot is acquiring the fissile material required for a bomb. But while that's the hardest challenge, it's not the only one. Terrorists would need to recruit people, transport materials, exchange funds, move operatives, and undertake experimentation and construction in order to pull off a plot. Counterterrorism and homeland security efforts that complicate each step, even if only slightly, can add up. In particular, they can deter would-be nuclear terrorists from pursuing that path in the first place.
Alas the fourth factor that explains the past decade is luck. There are still places beyond (and possibly within) Afghanistan that might make acceptable sanctuaries for nuclear plotters. Efforts to secure nuclear materials are far from complete--and some in Congress are now foolishly trying to cut them. Schemes aimed at optimizing homeland security to prevent nuclear terrorism have focused too much on deploying extraordinarily expensive detection machines and too little on integrating simpler technology with human assets. Luck is the only way to square such shortfalls with the lack of serious plots.
It is wrong to play Chicken Little when it comes to nuclear terrorism: Exaggerating risks itself has real consequences. But there is still much the United States can do to cut the odds of a devastating attack and ensure that a decade from now, it can still claim success.