The German government's purchase of data stolen from a Liechtenstein bank has reinvigorated longstanding debates about privacy, law enforcement and international relations. Much of the fallout has followed predictable patterns. Some argue that Germany's richest citizens should be brought to justice for failing to comply with the tax laws, while others point out that it is unseemly for a nation to spy on a peaceful neighbor. The conflict between Germany and Liechtenstein also has triggered a broader debate about tax competition and the role of so-called tax havens. The Paris-based Organization for Economic Cooperation and Development is trying to use...