1. Part of oil price decline is caused by stronger dollar. Major part is caused by increased supply from fracking of shale oil in N. America. 2. Stronger dollar is caused by improved American economy, compared with other developed economies, like EU and Japan. 3. Improved American economy is caused by Federal Reserve’s unconventional (expansive) monetory policy intiated by Bernanke, followed by Yellen (whose job seems to become easier than her predessor’s). 4. Obama’s contribution to this oil price decline is his support of Federal Reserve’s policy and nomination of Yellen who will continue to adjust US monetory policy according to economic development. 5. Yellen will face nomination hurdle in 2018 when her term is up. Hope winner of 2016’s presidential election will again nominate Yellen in 2018.