During the eight years I served as President Obama’s science advisor and director of the White House Office of Science and Technology Policy (OSTP), people not closely familiar with how the executive branch works often asked me why these roles exist: “Why does the president need a science advisor and a whole White House office focused on science and technology policy? What do they do?”

Every US president starting with Franklin D. Roosevelt in his third term has had a senior scientist or engineer advising him directly. A supporting full-time staff in the White House was added during President Eisenhower’s second term. Given this history (interrupted only briefly when President Nixon, unhappy with the advice he was getting, fired his science advisor and dissolved the corresponding White House office), one might suppose there are good reasons for the existence of these positions. My OSTP colleagues and I were always happy to explain what those reasons are. (Among many other venues, we did that on the OSTP website, archived here.)