http://en.wikipedia.org/wiki/Invasion_of_Grenada
Remember the Cuban Missile Crisis? The Soviets had to dismantle and remove nuclear delivery systems.
But Castro remained, and in my opinion, was still trying to put the strategic squeeze on the US. Castro saw his chance of bringing in Soviet Air Power to threaten US, and US interests in the Western Hemisphere, so he offered. His involvement with the revolution there is also problematic, there is no doubt in my mind he did more than give it moral support.
So I see this invasion as part of US-Soviet brinksmanship. Remember we had just withdrawn (a nice word for lost) in Vietnam, which was a Soviet Client state.
I am not so keen on seeing it as a redress to messing up in Cuba.
Describe how the strong United States action taken in Grenada was an attempt to redress an earlier American policy failure in Cuba.
2 answers
But we will be happy to critique your thinking on it, and in fact, on this issue, there is a variety of opinions of what happened and why. You can find quite a lot on Google.