One of the mysteries attending the eclipse of the political center and the rise of left and right, both in the United States and in Europe, is why it has taken so many by surprise. When economies fundamentally alter their course, to the detriment of most, a radical shift in nations’ politics — for both better and worse — shouldn’t be so astounding, particularly when an economy’s dysfunctions have been clear for many years.

The United States’ economic dysfunctions have been apparent for decades: The decline of manufacturing, which provided middle-income jobs to millions, and the burgeoning of the low-wage service sector were visibly underway by the 1980s. So, too, was the shrinking of unions, and with it, the ability of workers to bargain with their employers. By now, it’s clear that long-held beliefs about how an economy works — for instance, that declining unemployment should be accompanied by higher wages — need to be altered, or at least qualified. Since the depth of the Great Recession, in 2009, the unemployment rate has been cut nearly in half, but despite its decline over the past year to roughly 5 percent, wages haven’t budged, while median income and the rate of poverty, according to Tuesday’s Census Bureau report, have remained unchanged. A different litany of economic woes vexes most European nations, but on both sides of the Atlantic the belief that the economy generally produces broadly shared prosperity has been shaken, if not shattered.

Under these conditions, voters respond, and should respond, to political leaders who offer compelling explanations and solutions for the harsher economic realities. They respond to those who identify the culprits behind their troubles and say how they’ll diminish their sway. That’s why Donald Trump and Sen. Bernie Sanders (I-Vt.) have connected with millions of voters, and why politicians who haven’t gauged the depth of voters’ anger over the economy’s betrayal of their prospects and expectations have failed to connect.

This isn’t to equate Trump and Sanders; far from it. The centerpiece of Trump’s story — that undocumented immigrants are the villains in the tale of Americans’ downward mobility and rising crime rates — is preposterous: The slice of the workforce in competition with the undocumented is small, and crime rates have declined significantly since the great migration from Latin America and Asia began. Trump’s ability to win over more supporters than his rivals in the Republican field is due in part to his non-politician status, but what really sets him apart is that the story he tells connects more deeply with the racism and xenophobia of many within the Republican base — a racism and xenophobia that have grown steadily more apparent as the economy has stubbornly refused to improve.

A similar dynamic has shaped the European reaction to the massive wave of refugees flooding into the continent. Only two European nations — Germany and Sweden — have welcomed those refugees and taken them in in large numbers. Not coincidentally, two of the few European nations in which real wages have increased in recent years are Germany and Sweden. Rising economic tides not only lift all boats; they also predispose voters to welcome more boats into port. Fifty years ago, when the United States changed its laws to permit the entry of more immigrants and to scrap the quotas that effectively limited immigration to all but Europeans, American voters were in the midst of a decades-long boom characterized by unprecedented economic mobility and security. Whatever the racial and cultural phobias that many American whites may have harbored, their economic anxieties were at a low ebb. More immigrants? Sure. Civil rights laws? Okay.

Here are Donald Trump’s most memorable moments from the second GOP debate. (CNN)

If Trump is a candidate for an age of anxiety (albeit one who causes at least as much anxiety as he exploits), so is Sanders. The difference is that when Sanders identifies the culprits and cures for the hard times that have descended on us, he can substantiate his claims with reams of hard data. Profits have risen at wages’ expense; the ratio between top executives’ pay and that of their employees has soared; taxing financial transactions and raising the tax on investments to the level of tax on work will more adequately fund needed public programs; giving workers the power to bargain with their employers will help re-start the American mobility machine. The key to Sanders’s success, beyond his unchallengeable authenticity, is that the story he tells, the villains he calls out and the remedies he proposes are more accurate a portrayal, and more adequate a prescription, than those of rival candidates.

Capitalism in Europe and the United States is no longer yielding mass prosperity. That’s why the center isn’t holding, and why left and right are rising.

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