I'm kind of surprised these kind of operations aren't more frequently attempted. Plus, it would be relatively easy to "succeed" in the very short term -- the problem is in few cases would there be long term better governance as a result.
There's also Frederick Forsyth's "The Dogs of War", a work of fiction which may have been part of the inspiration behind both plots
(Forsyth was rumoured to have mingled with people preparing an actual coup in Equatorial Guinea whilst researching the book)
The history of post colonial governance in many African countries is a regular sequence of coups and coup attempts; it's a fair assumption that moneyed Western interests have played a role in sponsoring many of them and simply found existing local opposition groups and ambitious military generals to be a less risky option for conducting operations than foreign mercenaries.
(Back then it was Caribbean and Latin American states that were the usual targets, rather than African ones. But the same logic applies -- the targets were still relatively new post-colonial states, it's just that the colonial power that had most recently been losing its grip was Spain.)
I'm not exactly surprised that the CIA informed their torture-buddy Yahya Jammeh of the coup plans, but I am still sickened by it. If you fight evil African dictators, never talk on the phone, never post on social networks.
The [FBI] alerted the State Department, the Post reported, which in turn “secretly tipped off” an unnamed west African country – generally presumed to be Senegal – in the hope that it would intercept Sanneh. The coup plotters suspect that the information instead ended up in Jammeh’s hands. “When we, the people in prison right now, are going through this ordeal, Gambians are thinking: is the US hiding something?” Faal said. Later, after the Post story appeared, Faal added, “I would go so far as saying they killed Njaga. They are responsible for that.”
Article linked from TFA [0]:
I’m failing to see the friendly aspect of this all, save for the fact that Gambia and the Jammeh regime participated with the US in the CIA torture programme,” said Smith.
FBI and State knew about it, so obviously CIA did as well. (Presumably from NSA's extensive domestic monitoring, but I digress...) CIA had a previous relationship with Jammeh from their torture dungeons operated in the Gambia. The presidential guards were lying in ambush and knew the plan and timing of the attempted coup exactly. They only attacked the presidential palace because a planned Jammeh holiday trip to the countryside was cancelled at the last moment. I think we can read between the lines here.
It wasn't "doomed to fail" except in retrospect. The regime was tipped off as part of the continuing US policy to make sure that the dictators of the world die of old age.
Even if they had taken out the president, all of his political appointments would still be there. The most likely outcome is being immediately killed by the old military and replaced by some general mostly interested in keeping the status quo.
If they couldn't manage to get enough people, especially locals, for the coup what chance did they have of collecting enough loyal people to rule the country and transition it to Democracy?
Well presumably rounding up support locally whilst still trying to stay undetected is pretty hard. Realistically you'd probably only want to have enough people for the plan to succeed informed, any more and the chance of detection rises.
As it was, the U.S. tipped them off anyway and they were waiting for them, so they probably would have needed a lot of people to succeed.
I'm kind of surprised these kind of operations aren't more frequently attempted. Plus, it would be relatively easy to "succeed" in the very short term -- the problem is in few cases would there be long term better governance as a result.