While both of your terms would also be correct, major force is also correct, as established in the citations.  For your edification, let's take a look at the definition of major force (according to Webster's).  Major: "very important"; "notable or conspicuous in effect or scope". Force: "an individual or group having the power of effective action".  (most appropriate definitions per this usage).  Those would be a more accurate description of Haver's influence, as per the source.  I would suggest that you reflect on your edits, based on your opinion, without any back-up, before you continue your pattern of subjective editing. You provide subjective opinion, I cite sources, and give clear references. I have reverted your subjective edit, which you base solely on your opinion.  Might I further suggest, that we let other editors weigh in so that a consensus can be reached (which is proper Wikipedia policy)