CAMBRIDGE – The experience of the past three years has shattered the myth that the US Constitution on its own can protect American democracy from a narcissistic, unpredictable, polarizing, and authoritarian president. But the country’s problems are not limited to the menace in the White House. All Americans also bear responsibility for the current state of affairs, because we have neglected critical institutions and ignored the intensifying structural weaknesses that created the conditions for a demagogue like Trump to emerge in the first place