The plunge in oil prices

Of course most of us are happy with the drop in oil prices, but I cant help but wonder why it has dropped so far so fast. The only reason I can come up with is obama's  failed energy programs. I know, it sounds as though that doesn't make sense.  He came in with promises of alternative energy sources but just wound up throwing tax payers dollars onto the sun and watching them burn up. It was just about the time of the mid term elections when the plunge began and here is what I feel the reason is. OPEC knew that the Dems were going to lose control and there would be a good chance the GOP would get the Keystone Pipeline approved (it did just pass in the senate 62-31, 67 votes needed to avoid a veto) so they would let prices plunge so there wouldn't be much pressure on the Dems to get more oil production/lower prices from North American sources.  I am interested to see if it passes will OPEC cut their production levels, and the same if obama   manages to veto the bill. Is it even possible that obama was in collusion with OPEC just to get his whiny, self righteous, arrogant way? It is not too far fetched. After all everything he does seems to be more about his legacy than the good of the people.