I'm not so sure they did. The idea is that if you are of interest to a powerful adversary, then a second powerful entity that has previously collected pertinent

I'm not so sure they did. The idea is that if you are of interest to a powerful adversary, then a second powerful entity that has previously collected pertinent coercive knowledge about you could try to strike a deal using that information they collected, potentially decades ago. Or they could threaten to release the info unless you compromise your positions. Besides, surely in the future there could be a more automated intelligence brokerage between nations - who knows how long the current political climate lasts before it gets replaced with something more like HFT intelligence trading between the MSS and NSA.