U.S.-EU cooperation against terrorism has led to a new dynamic in U.S.-EU relations by fostering dialogue on law enforcement and homeland security issues previously reserved for bilateral discussions. Nevertheless, some challenges persist in fostering closer U.S.-EU cooperation in these fields. Among the most prominent are data privacy and data protection concerns.
The September 11, 2001, terrorist attacks on the United States and the subsequent revelation of Al Qaeda cells in Europe gave new momentum to European Union (EU) initiatives to combat terrorism and improve police, judicial, and intelligence cooperation among its member states. Other deadly incidents in Europe, such as the Madrid and London bombings in 2004 and 2005 respectively, injected further urgency into strengthening EU counterterrorism capabilities and reducing barriers among national law enforcement authorities so that information could be meaningfully shared and suspects apprehended expeditiously. Among other steps, the EU has established a common definition of terrorism and a common list of terrorist groups, an EU arrest warrant, enhanced tools to stem terrorist financing, and new measures to strengthen external EU border controls and improve aviation security.