Donald Trump sworn in as the 47th President of the United States
Donald Trump has been sworn in as U.S. president, ushering in another four-year term with promises to push the limits of executive power, deport millions of immigrants, secure retribution against his political enemies and transform the role of the U.S. on the world stage. Trump's inauguration completes a triumphant comeback. We speak with Historian Sean Wilentz, a professor of history at Princeton University.