The US and European Union are right now negotiating an agreement on how to share the personal data of citizens for use in national security and law enforcement investigations, a process many privacy advocates fear will lead to a weakening of protections in Europe. Nearly a dozen civil liberties groups in the US have written to President Obama and congressional leaders urging American negotiators to support a framework that would strengthen US privacy rules rather than degrade the relatively stronger safeguards that exist in the EU.

It appears, however, that the US appetite for personal data collection in combating terrorism, which has grown in the wake of 11 September, may trump Europe’s historic reluctance to monitor and collect data on its citizens. This tension was apparent as European negotiators spoke Tuesday in Washington at an annual conference on Computers, Freedom and Privacy.

“After World War II, Germans and Europeans have sworn ‘never again;,” said Jan Philipp Albrecht, a member of the European Parliament from the German Greens. “This means never again should there be violence, mass murder. But never again should there be repressed and unfree people. I think what we are struggling for today is exactly this.”

The personal data at stake in the negotiations includes airline passenger data and information on financial transactions — all of which may be collected, shared and retained by government agencies in ways privacy advocates fear could infringe on the rights of even individuals unconnected to legitimate law enforcement investigations.

“In the EU there is still a widespread perception that data exchanges have been largely a one-way street over the past few years,” said Frank Schmiedel, a member of the EU delegation to Washington. “I keep joking that US authorities know our own citizens better than our own authorities. So we’re right to insist on more transparency, more protection of our rights, of the rights of Americans and Europeans alike irrespective of nationality. And more reciprocity, more sharing of derived intelligence from this data.”

“To paraphrase President Kennedy,” Schiedel later added, “don’t always ask when it comes to data protection and data what Europe can do for you. Also ask yourselves what you can do for Europe to assuage our concerns.”

The negotiations have received almost no public attention in the US, unlike in the EU, an indication of the fact that Europeans have much more to lose in them.