If Barrack Obama wins the presidency, the price of oil could fall by $40 per barrel. The financial markets will discount the possibility before hand, at least partially. There are three ways in which this could happen:

1) As was the case during the Clinton administration, Obama might be more inclined to intervene in the foreign exchange market to support the value of the dollar. The U.S. has not intervened in the FX market since Treasury Secretary Robert Rubin did so in September 2000 when the Treasury sought to support the Euro, then costing about 80 cents per dollar (yes, the cost has almost doubled since then). Intervention or the threat of intervention could shave $20 off the price, based on the divergence in price between oil quoted in dollars versus that of other currencies.