America's global legacy at 250

As the United States grew from a series of small colonies into a global superpower, it took bold, transformative steps on the world stage, but it has also stumbled.

On this 250th anniversary, guest moderator William Brangham, Esther Brimmer, Michael Mandelbaum and Robert Zoellick examine America's global legacy and what history will teach us about President Trump's foreign policy. ...