http://www.rawstory.com/news/2007/Convicted_Watergate_plumber_claims_LBJ_may_0114.html
\ Howard Hunt the famous watergate CIA operative has a book coming out implying Johnson was in on JFK assassination and as many as 10 others.
The hits keep on coming. We can now start over.
CIA’s mind control MK-ULTRA project: MKUltra - Wikipedia
Particularly vile – have a look at what they were doing to unsuspecting Canadians in Montreal. Coincidentially, one of my clients was a subject in these tortures.
Somewhere in the CIA offices, alarm bells are going off as an NSA computer reads your post, and agents are having to figure out a discrete way to cure the cancer they just gave Chavez and replace it with Mad Cow Disease. 
Actually, I’m imagining a scenario where the victim doesn’t have any Big Secret, but his death would be convenient for the government. The current president of Venezuela (Hugo Chavez) might be a good candidate for this sort of treatment. He’s constantly butting heads with the US, and his radical socialist stances are beginning to threaten US interests down there. (He’s talking about nationalizing various industries that US companies are involved in.) It’s conceivable that the CIA might decide to off him, but for political reasons a traditional assassination would be unfeasible. The “cancer drug” (or whatever this method is supposed to use) would be attractive in this situation. Just give ol’ Hugo brain cancer, and within a year you’ll be talking about him in the past tense.
As for Aleksandr Litvinenko, I’d say that’s a pretty clear case of killing someone to send a warning to others. The Russians deliberately chose an assassination method that would guarantee a horrible, painful death. There’s an element of revenge there, but the main point was to scare anyone else who might be thinking about revealing his secrets. It’s not unlike when the Mob kills an informant, and the cops find the guy in a garbage pile, with a rat in his mouth and money shoved up his ass. If you were a mobster who was thinking of sqealing, you’re damn sure going to have second thoughts when you hear about what they did to that guy.
The part above (bolding mine) is what I’m having trouble with. How are they going to communicate this to the other potential blabbermouths? Do spies have a newsletter, or a circulation that they read? Do they hang out in the cafeteria and swap stories? How exactly would they hear about the death of another spy?
Obviously the guy died, and was killed by a deliberate cold-blooded use of highly radioactive toxic stuff. I don’t question that part. It’s just puzzling that someone would use a weapon that can be tracked with a Geiger counter, on the assumption that the other spies would find out about it. How, precisely, would that happen? I just don’t envision secret agents as being, well, social and well-informed about the nature and identity of other secret agents — I don’t know if I believe in a “grapevine” where spies would all know each other and chatter about “hey, did you hear what happened to Alex?”
Doesn’t the whole concept of threat, in this case of spies or informants, rely on the international publicity to work?
As for giving some foreign leader cancer simply because he’s inconvenient, it sure seems like a cumbersome way to do things. This is especially true if the first thing that leaps to everyone’s mind when they hear a politically valuable person gets cancer is “the government did it!” Kinda defeats the purpose.
years ago, I read about some of the CIA’s shenanigans in the Philippines-by a guy named Fletcher Prouty? Anyway, the “Hukbalahap” (communist) guerillas were running wild in central Luzon. the CIA captured a few, and killed them-and punctured the necks on the bodies (like a vampire would). The bodies were left in the jungle, where villagers would find them-and the people were so terrified, that the insurrection ceased.
I have no doubt that the CIA pulkled all kinds of stunts-but most of this stuff will never be declassified.
It’s called “the evening news.” It’s no accident that Litvinenko was hit in public, in a very unusual and news-worthy way. The Russians wanted the publicity, and the media sent their message for them: “People who betray Russia will die a horrible death.”
You can’t tell me that the microphone going off the air right as Barry Bonds hit his 715th homer was mere coincidence. 
Fools!
It should be green!
Its not strictly speaking a US conspiracy (though the US via James Angleton and the CIA were certainly involved). But I’d say the plot to depose the British Prime Minister during the 1970’s certain falls under that category:
The Tuskegee experiment went on for 40 years and never came out. There were at least hundreds and maybe thousands that could have broke it and did not. So it would be possible to keep something horrible under wraps for many years.