Chatham house are famous for the rule that if you're invited, you agree that if you talk about what they talked about in their meetings, you must not say who said it.

Most political manipulation of influential people isn't sophisticated at all, it's 3rd grade bullying level. For instance, getting invited to an exclusive meaning as proof of your importance/"seriousness". Brazen flattery, but it works.

And the secrecy grooms them into betraying outsiders in favor of insiders. It's not such a big betrayal to give cover to powerful people's ugly opinions, but it's a start. And once you've done one bad thing with the gang, you're easier to persuade to do worse things with the gang. Again, really banal stuff.

Remember in Snowden's biography, he mentioned being involved in a plot to get some diplomatic person to drunk drive, so they could swoop in and "help" him. That wasn't just targeted at the diplomat. It was also targeted at rookie CIA agent Ed: first do iffy things with us, so that you have firmly rationalized and justified it to yourself once we ask you to do uglier stuff.