Could a President Hillary instantly lower the price of oil?

"Hillary Clinton predicted Saturday that just electing her President will cut the price of oil. When the world hears her commitment at her inauguration about ending American dependence on foreign fuel, Clinton says, oil-pumping countries will lower prices to stifle America's incentive to develop alternative energy. "

Let's say that Hillary is elected President and the world believes that she will indeed cause the U.S., in a decade or so, to use far less oil. What would happen to the price of oil in the short term?

Most likely, oil companies would spend far less money developing new oil wells and building new refineries. As a result, the supply of oil would fall causing short term oil prices to rise.