CAMBRIDGE (Massachusetts) • The election of Mr Donald Trump in the United States and the triumph of Brexit in the United Kingdom - the two political earthquakes of 2016 - resulted from the failure of the elites to grasp the discontent roiling politics in democracies around the world. The populist revolt marked the rejection of a technocratic approach to politics incapable of understanding the resentments of voters who feel that the economy and the culture have left them behind.

Some denounce populism as little more than a racist, xenophobic reaction against immigrants and multiculturalism. Others view it as a protest against the job losses brought about by global trade and new technologies. But to see only the bigotry in populist protest, or to view that protest only in economic terms, misses the fact that the upheavals of this year stemmed from the establishment's inability to address - or even adequately recognise - genuine grievances.

The populism ascendant today is a rebellion against establishment parties generally, but centre-left parties have suffered the greatest casualties. This is mainly their own fault. In the US, the Democratic Party has embraced a technocratic liberalism more congenial to the professional classes than to the blue-collar and middle-class voters who once constituted its base. A similar predicament faces Britain's Labour Party.

Before they can hope to win back public support, progressive parties must rethink their mission and purpose. To do so, they should learn from the populist protest that has displaced them - not by emulating its xenophobia and strident nationalism, but by taking seriously the legitimate grievances with which these sentiments are entangled. And that means recognising that the grievances are about social esteem, not only about wages and jobs.

Progressive parties need to grapple with four main issues:

•Income inequality

The standard response is to call for greater equality of opportunity - retraining workers, improving access to higher education and combating discrimination. This is the meritocratic promise that those who work hard and play by the rules should be able to rise as far as their talents will take them.

But for many, this promise rings hollow. Even in the US, with its long-cherished dream of upward mobility, those born to poor parents tend to stay poor as adults. Of those born in the bottom fifth of the income scale, 43 per cent will remain there, and only 4 per cent will make it to the top fifth.

Progressives should reconsider the assumption that social mobility is the answer to inequality. They should reckon directly with inequalities of wealth and power, rather than rest content with efforts to help people ascend a ladder whose rungs are growing further and further apart.

•Meritocratic hubris

The problem runs deeper. The relentless emphasis on seeking a fair meritocracy, in which social positions reflect effort and talent, has a morally corrosive effect on the way we interpret our success (or lack thereof). The belief that the system rewards talent and hard work encourages the winners to regard their success as their own doing, a measure of their virtue - and to look down upon the less fortunate.

Those who lose out may complain that the system is rigged, or be demoralised by the belief that they alone are responsible for their failure. When combined, these sentiments yield a volatile brew of anger and resentment, which Mr Trump, though a billionaire, understands and exploits. Where Mr Barack Obama and Mrs Hillary Clinton speak constantly of opportunity, Mr Trump offers blunt talk of winners and losers.

Democrats like Mr Obama and Mrs Clinton have difficulty understanding the hubris a meritocracy can generate, and the harsh judgment it renders on those without a college degree. This is why one of the deepest divides in American politics today is between those with and without post-secondary education.

•The dignity of work

The loss of jobs to technology and outsourcing has coincided with a sense that society accords less respect to working-class occupations. As economic activity has shifted from making things to managing money, with hedge fund managers and Wall Street bankers receiving outsize rewards, the esteem accorded work in the traditional sense has become fragile and uncertain.

New technology may further erode the dignity of work. Some Silicon Valley entrepreneurs anticipate a time when robots and artificial intelligence will render many of today's jobs obsolete. To ease the way for such a future, they propose paying everyone a basic income. What was once conceived as a safety net for all citizens is now offered as a way to soften the transition to a world without work. Whether to welcome or resist such a world is a question that will be central to politics in the coming years. To think it through, political parties will have to grapple with the meaning of work and its place in a good life.

•Patriotism and national community

Free-trade agreements and immigration are the most potent flashpoints of populist fury. On one level, these are economic issues. Opponents argue that they threaten local jobs and wages, while proponents maintain that they help the economy in the long run. But the passion evoked by these issues suggests that something more is at stake.

Workers who believe that their country cares about cheap goods and cheap labour more than it cares about its own people's job prospects feel betrayed, and they often express it in ugly ways: hatred of immigrants, nativist vilification of Muslims and other "outsiders", and demands to "take back our country".

Liberals reply by condemning the odious rhetoric and insisting on the virtues of mutual respect and multicultural understanding. But this principled response, though valid, fails to address some big questions implicit in the populist complaint. What is the moral significance, if any, of national borders? Do we owe more to our fellow citizens than we owe citizens of other countries? In a global age, should we cultivate national solidarity or aspire to a cosmopolitan ethic of universal human concern?

Establishment elites, especially in Europe and the US, are now confronting the consequences of their failure to address these questions. The populist revolt highlights the need to rejuvenate democratic public discourse, to address the big questions people care about, including moral and cultural issues.

Disentangling legitimate grievances from the intolerant aspects of populist protest is no easy matter. But it is important to try. Creating a politics that can respond to these grievances is the most pressing political challenge of our time.

PROJECT SYNDICATE

•Michael J. Sandel teaches political philosophy at Harvard University. His books include What Money Can't Buy: The Moral Limits Of Markets and Justice: What's The Right Thing To Do? His BBC programme The Global Philosopher gathers participants from around the world to debate current issues.