No Republican politician illustrates the power and peril of Donald Trump and his takeover of the G.O.P. quite like New Jersey's two-term governor, Chris Christie. Christie, once the exemplar of Republican pugilism, went from competitor to wingman in Trump's successful rise to the presidency only to become his most outspoken antagonist. How does a man who has seen it all think the United States arrived at this juncture and what does he think the future holds?

Featuring former Governor of New Jersey Chris Christie in conversation with Leigh Ann Caldwell, American political reporter for The Washington Post.