I'm sure that such things have happened, and it's not just a question of the CIA. There are a number of other covert organizations which might have engaged in such activities, with or without connections to the CIA. There's a whole network of paramilitary and intelligence and counter-intelligence type outfits involved in training people for moving weapons, moving drugs, laundering money, spying, setting up paramilitary forces in Third World countries, setting up coups in Third World countries, carrying out assassinations, supplying personnel for death squads and interrogation...it goes on and on.

Look into the history of Guatemala, for instance, or Panama, or Nicaragua, or Chile, or Peru, or Southeast Asia, or Iran...

Now, these people do not just work outside of the USA. They work within the USA as well, and they represent some of the most dangerous and powerful people in the country.

If a president gets seriously in the way of those people, I'm sure they have a number of ways to remove him from office.

The important thing I would think in such organizations is that the underlings, the foot soldiers, know as little as possible...only enough to do their part of the job. That way they don't become much of a security risk if they get caught.

I think that Lee Harvey Oswald was one of those underlings...a little fish that got caught up in a very big scheme, and one not of his own making.