The Coventry story dates back to Winterbottom's "The Ultra Secret", the book that first broke Ultra around 1973. Later books by respected authorities like Dr. R. V. Jones, head of the British electronic countermeasures during the war, dispute the account. Dr. Jones, considered the Father of ECM, wrote that at the time of the Coventry raid, they did know something was up for that night but Ultra didn't specify the exact target. He claims that during the Fall of 1940, only a small percentage of Ultra intercepts were being broken. Coventry was bombed because they didn't break the code for that day and were unable to jam the German navigation signals, not because Churchill sacrifaced the city.

For the rest of the war, the Allies went to extreme lengths to protect Ultra. For example, in the Mediterrian theater, Ultra might tell of a German convoy bound for North Africa. However, they wouldn't attack the convoy until a reconnaissance plane "found" it. The Germans were convinced that Ultra was unbreakable and the Allies did everything possible to prevent them from findng out otherwise.

Sometimes, you have to protect sources for a long time after the fact. In the case of the hypothetical agent in Iraq, his identity might need to be protected for the rest of his life.

The Ultra experience does point out how sensitive sources are protected. In the case of Ultra, it was highly classified until Winterbottom was allowed to publish the first book about it almost 30 years after the war ended.

A week ago, the Discovery Wings channel broadcast a program about "Project Alpha" which happened in 1953. The program was filmed in 1996 but I saw it for the first time last week. In 1953, agents from a Balkan country contacted the US embassy and offered them an opportunity to test fly a Soviet Yak-23 fighter. The plane was boxed up and being shipped across the country. An Air Force C-124 picked up the box and flew it to Wright-Patterson AFB, Ohio. The contents were carefully photographed and the plane was assembled. It was test flown by an American test pilot, then disassembled and put back into the shipping crate exactly as it was before. It was flown back to the country and the Soviets never were the wiser. Interestingly enough, the story wasn't declassified until 1991 and the country involved was still classified at the time of the 1996 filming. Some secrets are kept for a long time.

In the case of the Cuban missile crisis, our only photographic reconnaissance satellite was the Corona. It was super classified at the time and the resolution was somewhere around 3 meters. When the Cuban missile base photos were shown to JFK, he had a hard time comprehending what he was seeing. The Air Force took more photos with U-2 spy planes (public since Francis Gary Powers was shot down 2 years earlier over Russia) for higher resolution images. They later took low altitude photos from RF-101 Voodoo recon planes that were undisputable.

When Kennedy released the photos, they were the pictures from the RF-101 and perhaps the U-2, but not the more sensitive Corona photos. Even in the face of possible nuclear war, they didn't compromise the source.