The President effects the economy through the policies they choose to do or not do. reason gas prices were so low under trump he opened up more drilling in the usa got less oil from over seas thus OPEC LOWERED PRICES less demand thus our oil in our country fell in prices its economics 101 supply demand. lower oil prices reflect in lower gas prices reflect in lower prices for goods cause shipping costs are lower. Bidens first week in office canned the pipeline so that stoked fears his camping was on pushing oil out fracking drilling processing thus fear in the market we started producing less asking OPEC FOR MORE. in return prices went up.