Am I missing something here? A statistically relevant subset of people have important secrets, and a statistically relevant subset of those (perhaps most) are relatively easy to control when you know them. If the US has similar information on other governments' personnel, we might even fall into the caricature of the US guiding their actions while they guide those of the US, since those controlling and those being controlled will (largely) not be the same members of their respective governments.
The entire situation seems quite messy.