Can we use falling oil prices against our enemies?

Venezuela and Iran both depend almost entirely on oil revenues to keep their America hating governments in power. Since they spend so much on defense and public works and public welfare, a sudden decline in revenue spells their doom. They also have inferior oil compared to other countries which means theirs costs more to extract and refine, meaning that oil below a certain value literally prices Venezuela's and Iran's oil out of the market. Is there a way we can take advantage of the fall of the price of oil and sink those America hating regimes?