On Thursday's broadcast, Gwen Ifill talks to historian and NewsHour regular Richard Norton Smith and journalist Carl Cannon about failed presidential candidates who still managed to change political history. The subject is explored in a C-SPAN series starting…

Traders work on the floor of the New York Stock Exchange on Thursday. Photo by Jin Lee/Bloomberg via Getty Images Editor's Note: Given the rollercoaster behavior of the stock market over the past few weeks, we checked…