President Donald Trump went to Iowa on Thursday to start the countdown to the nation’s 250th Independence Day next year. To mark the anniversary, the nonpartisan Center for the Study of the Presidency and Congress is looking at 250 years of U.S. innovation. John Yang speaks with Glenn Nye, the center’s president and CEO, about the project. PBS News is supported by - https://www.pbs.org/newshour/about/funders