In the world of international politics it is an open secret that diplomats are spies as well as negotiators. It is part of the job of the diplomat to gain as much intelligence on the host country as he possibly can. Sometimes this may involve fucking another diplomat.
Hooking up with an aide in an embassy or some other select position could potentially yield a great deal of useful information for the country that employs the diplomat. While the diplomat is representing his nation he’s always looking for valuable clues that could point him in the direction of possible sources of information and he may well pass that on to the intelligence agencies of his country. They in turn may begin checking that persons background, looking for a way in. A way in is a way in which they can open that person up for intelligence uses. It may be Free sex or money. It could be any number of things. The intelligence agencies as well as the diplomat must probe for weaknesses in their character and other means by which they can exploit the person. They may have an inordinately large appetite for Free sex in which case the intelligence agency will simply furnish them with the perfect temptation. They may be heavily in debt and the intelligence agency offer to pay that debt for them. It could be that that person wants to defect in which case it too might be discussed depending on the value of the intelligence that person has to offer. It is basically the job of the diplomat to be the eyes, ears, and mouth of the country that employs him and this means doing his best to find every advantage he can. Then he passes it on and his government decides how best to use that advantage.
Sometimes it is a game of the deadly serious while others it is a more relaxed and openly known game such as might be the case between friendly nations.