There are a number of effects, some negative and some positive. Mercenaries do not usually work with others or in a network which makes them more difficult to track. In the case of the John Walker spy ring, for example, which was almost all family, once one was arrested the rest quickly turned in the others. But ideologues will do almost anything to protect their comrades. Just look at Julius and Ethel Rosenberg, who went to their deaths rather than reveal what they knew of the truth about the network of Soviet atom spies that evidence now shows reached all the way up to Robert Oppenheimer and his wife, Kitty.
Espionage remains important, but remember that it has two faces.
There is the one side which is simply obtaining information some government feels it needs from us. Then there is the other side of the coin, which involves gaining influence. This is the element of spying in which the point is to put information or disinformation into the press or the government as a means of influencing U.S. public opinion or policy. We see this with the Chinese, who have infiltrated our political system to promote the sale of our dual-use technologies. When it comes to technical secrets, if we are willing to let our guard down it doesn t matter what the FBI does because America s adversaries are going to get them.