Remember, this isn’t a history paper.  Do not submit lengthy recitations of historical events.  Including some history is OK as long as it is pertinent and clearly supports your BLUF.  Include only the facts, evidence, data, etc. that supports your main point.  In the intelligence world, consumers often have very little time to read a written product so the analyst needs to clearly get his/her most important points across clearly right up front.  The consumer may just read the first part and skim the rest of the document.