It’s very hard (or impossible) to manipulate prices like that. To answer your first question, inventories are up for reasons analagous to RE inventory: oil prices were going up so much and so fast in the recent past, that many companies (even non-oil companies!) got in the game.
It looked like a fool-proof way to make money: buy oil, then sell it at the same time in the futures market, for a nice, risk-free profit. Even after factoring-in the price of storage, these companies made a lot of money. But too many did the same thing at the same time, worsening the oil shortage (and high price) in the short-term. Up to a point, of course. Now everybody has a big chung of oil to unload, and prices are moving accordingly (downwards!).
Unlike SFHs, oil prices are not sticky on the way down. (Retail gasoline prices are coming down, though not as fast as crude). At the same time, demand is contracting as the economy enters a slower growth period.
This has nothing to do with the political cycle, IMO. Politicians perhaps wish they had that kind of power in international markets!
