What Drives Populism — Culture or Economics?

Or do they reflect many voters' economic anxiety and insecurity, fueled by financial crises, austerity and globalization?

Much depends on the answer.

If authoritarian populism is rooted in economics, then the appropriate remedy is a populism of another kind - targeting economic injustice and inclusion, but pluralist in its politics and not necessarily damaging to democracy.

If it is rooted in culture and values, however, there are fewer options. Liberal democracy may be doomed by its own internal dynamics and contradictions.

Some versions of the cultural argument can be dismissed out of hand.

For example, many commentators in the United States have focused on Trump's appeals to racism. But racism in some form or another has been an enduring feature of US society and cannot tell us, on its own, why Trump's manipulation of it has proved so popular. A constant cannot explain a change.

Other accounts are more sophisticated. The most thorough and ambitious version of the cultural backlash argument has been advanced by my Harvard Kennedy School colleague, Pippa Norris, and Ronald Inglehart of the University of Michigan.

In a recent book, they argue that authoritarian populism is the consequence of a long-term generational shift in values.

As younger generations have become richer, more educated, and more secure, they have adopted "post-materialist" values that emphasise secularism, personal autonomy and diversity at the expense of religiosity, traditional family structures and conformity.

Older generations have become alienated — effectively becoming "strangers in their own land." While the traditionalists are now numerically the smaller group, they vote in greater numbers and are more politically active.

Will...