Under the U.S. Constitution, presidents have certain limited powers, but in the 21st Century, the president also controls a huge machinery of government. It’s almost impossible to come up with an exhaustive list of all the things presidents exercise authority over, but we’ve started such a list. We’ll be doing a series, with each post describing one or more categories where presidents are heavily involved. Please take a look at the series, and you will see the difference between having a Republican and a Democrat in the White House, and why the 2016 elections are therefore so crucial: