The Declaration of Independence states that "all men are created equal," but for much of U.S history that has been an aspirational ideal, according to Suzanne Mettler, a professor of government at Cornell University. Now the pillars of American democracy, including the rule of law, the legitimacy of opposition and free and fair elections, are under attack like never before, she explains.

Mettler, the co-author of Four Threats: The Recurring Crises of American Democracy, says that while the challenges aren’t new, their confluence under President Donald Trump has led to the weakening of the very necessary checks and balances built into our political system.