 Responding to the firestorm of controversy over its spying on European allies, the head of the National Security Agency said today it would do everything in its power to avoid being caught doing it in the future. There are two important jobs for every spy agency: spying on people and avoiding detection, said the N.S.A. chief General Keith Alexander. Unfortunately, at the N.S.A. we have only done the first job well. We have abused the trust of some of our closest allies, he said. And none of this would have happened if they hadnt found out. General Alexander said that the agency was instituting strict new practices that amounted to a zero-tolerance policy on getting caught. I had a meeting with my top people today and said, I want you to put the same energy you put into spying on Germany, France, and Spain into keeping them from figuring out what were up to, he said. Anything less than that will be unacceptable. General Alexander also offered a heartfelt apology to German Chancellor Angela Merkel, a prime target of the agencys eavesdropping. I know how upsetting it must be for you to know that your closest ally has been listening in on your phone conversations for the past eleven years, he said. I give you my solemn promise that in the future you wont know. 