Re: Meaning of the sentence
Here's another approach.
This is the first thing I want to say: The Organization of American States repealed its 1962 resolution excluding Cuba.
The Organization of American States did this at its 2009 meeting in Honduras.
The membership of Organization the of American States is coterminous with the membership of the recent summit -- I have NO IDEA what this means.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.