Foreign Ministry guys don't become agents. Party officials, the Foreign Ministry nerds, tend not to volunteer to Western intelligence agencies.

Another factor is the decision, made in 1976, to sharply divide the FBI and the foreign intelligence agencies. The FBI would collect within the United States; the foreign intelligence agencies would collect overseas.

You can't come forward against the world's most powerful intelligence agencies and be completely free from risk.

In the fight against terrorism, national agencies keep full control over their police forces, security and intelligence agencies and judicial authorities.

You have multiple intelligence agencies. They all ultimately report to the director of national intelligence but, you know, it never comes in neat packages. So you have to make judgments on what you have, and it's not easy to do.

Intelligence agencies keep things secret because they often violate the rule of law or of good behavior.