Bernie Sanders and Donald Trump with differing ideas on fighting oil prices

Sen. Bernie Sanders wants to stop oil speculation to combat the rise of oil prices.  A link to a Huffington Post article about it with a letter to the President included here.  A little bit different then Donald Trump's idea of just telling OPEC what their production levels should be with some colorful language.  How presidential of him. Interesting that he wants to control production levels of a global commodity, how is this capitalism?