The September 2001 attacks forced an uncomfortable realisation on Washington: the Hamburg cell that helped plan them lived inside the European Union, not just inside Germany. US investigators turned first to bilateral channels, long-standing extradition and mutual legal assistance treaties with Berlin, but within months the Bush administration made a counter-intuitive choice. It decided to negotiate with the European Union as an entity, despite the fact that the EU then possessed no criminal investigators, no prosecutors, and no treaty-making capacity in justice affairs under its founding treaties.
Why Brussels, not Berlin or Paris
The push came from Brussels. Gilles de Kerchove, the EU's senior career official for Justice and Home Affairs, and Mark Richard, the Department of Justice's man in Brussels, floated a formal cooperation agreement within weeks of the attacks. Washington's initial reaction was bafflement. The United States already had mutual legal assistance treaties with the major member states and a comprehensive web of bilateral extradition treaties. Why add a layer of EU complexity?
The answer, as the White House later explained to the Senate, was efficiency. A single EU agreement could modernise the entire network of existing bilateral treaties at once, replacing outdated offence lists with a modern dual criminality standard. It could also create legal assistance relationships with the newer member states, many of them former Soviet bloc countries, with which the US had no treaties at all. "This is particularly important in light of the counterterrorism challenges we have faced since September 11, 2001," the administration told senators.
The legal engineering of the 2010 agreements
There was a further obstacle: the EU did not yet possess international legal personality, a prerequisite for treaty capacity under international law. That defect would not be cured until the Treaty of Lisbon in 2009. EU lawyers argued that the union had already concluded agreements with the successor states of Yugoslavia in the 1990s, demonstrating an 'effective' legal personality. State Department treaty lawyers accepted the argument, and the extradition and mutual legal assistance agreements were signed in 2010.
The extradition agreement replaced exhaustive, dated offence lists with the dual criminality approach, if an act is criminal in both jurisdictions, it is extraditable. This brought terrorism, cybercrime, money-laundering and sexual exploitation offences into scope across the board. The mutual legal assistance agreement went further: it created a legal basis for video depositions of witnesses located in the other party's territory, with the resulting evidence admissible in the requesting state's courts. Before this, several member states could not offer such assistance. An EU study later found US prosecutors using video depositions taken in Europe with "increasing frequency and effectiveness," a tool that proved vital during the coronavirus pandemic.
Passenger data: airlines caught between two legal orders
While the treaties were being negotiated, the Department of Homeland Security launched a programme under the 2001 PATRIOT Act requiring airlines to hand over Passenger Name Record (PNR) data, addresses, phone numbers, credit card details, even meal preferences, for advance screening of every transatlantic flight. European privacy law blocked unilateral transfers. Airlines, facing conflicting legal obligations, begged Brussels for a solution.
Negotiating a sustainable PNR agreement took eight years. A 2004 deal was annulled by the Court of Justice of the European Union. A successor collapsed under political pressure from the European Parliament. The durable text finally arrived in 2012, embedding EU-derived data protection safeguards that DHS accepted in return for continued data flows. The Commission later reported the agreement had been especially valuable in preventing the return of foreign fighters to EU territory and in child exploitation and drug cases. DHS has not published a detailed scorecard but disclosed examples, the most striking being the 2010 arrest of Faisal Shahzad. After a failed car bomb in Times Square, investigators matched a recovered phone number to the PNR database and detained Shahzad aboard a Dubai-bound flight at JFK the same day. He is serving a life sentence.
Banking data and a parliamentary revolt
The Terrorist Finance Tracking Program followed a similar arc. After 9/11, the Treasury Department served administrative subpoenas on SWIFT's US facility, quietly obtaining vast tranches of global financial messaging data. The New York Times exposed the programme in 2006, triggering outrage in Europe because the data included transactions by EU citizens protected by EU privacy law. SWIFT responded by planning to close its US offices, which would have stripped the subpoenas of jurisdictional reach. Treasury needed an EU agreement to access data from SWIFT's Belgian headquarters.
The Council of the European Union reached a deal in late 2009, but in early 2010 the European Parliament refused consent, the first time it had ever vetoed an EU international agreement. A revised text barely survived a second parliamentary vote later that year. The EU assumed an unusual dual role in implementation: each Treasury request for SWIFT data is first assessed by an EU-appointed independent overseer before transmission, a structure designed to embed proportionality and necessity checks into the process.
What the EU gained: a seat at the table
For the EU institutions, the agreements were never only about operational utility. They were a vehicle to make Brussels relevant in a domain, criminal justice, that the treaties reserve to member states. The US agreed: the agreements would "enable the strengthening of an emerging institutional relationship on law enforcement matters between the United States and the European Union, during a period when the EU is actively harmonising national criminal law procedures and methods of international cooperation." Periodic joint reviews now bring together US agencies, the Commission, and member states to assess performance and troubleshoot implementation. Criminal law remains largely national, but the EU has become a genuine interlocutor in transatlantic counterterrorism.
People mentioned
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Gilles de Kerchove
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Mark Richard
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Faisal Shahzad
Organisations
European Union · US Department of Homeland Security · US Department of the Treasury · Society for Worldwide Interbank Financial Telecommunication · Court of Justice of the European Union · European Parliament
