LONDON — Vera Lengsfeld first realized the state was spying on her when cars started appearing outside her home. It was 1982, and cars were rare enough in Communist East Berlin to stand out — especially in groups of three.

Soon, young men lingered in the staircase leading to her apartment. Her telephone was bugged. When Ms. Lengsfeld and her husband wanted to discuss something private, they took a walk.

Except, as she learned after the wall had fallen and the files of the former secret police, the Stasi, were opened, her husband was one of 49 informers reporting on her. When it comes to privacy, Ms. Lengsfeld, 61, a writer and member of the Christian Democrats, knows exactly where she stands: “I have the greatest concern about secret services of any kind, even those in a democracy.”

In a country that produced both the Gestapo and the Stasi, now global synonyms for secret police terror, the National Security Agency’s spying program has caused outrage, raising the question: Is this German exceptionalism as we know it, or is it a harbinger of how the mood in Europe might be shifting, of how America’s trust problem has taken on a new corrosive quality?