As anyone trying to maintain perspective when the whole world seems to be losing it, I owe Joni Mitchell – big time. The reasons are too numerous to list here, but one involves her 1991 recording of the 1919 W.B. Yeats poem The Second Coming. It introduced me to that haunting work, in which post-First World War politics becomes an allegory for the Apocalypse, or vice versa.

There have been plenty of times since 1919 when commentators have turned to Yeats to explain political phenomena that defy ordinary prose. The poem has proved especially handy as Donald Trump lies, rants and hate-tweets his way to the U.S. presidency.

What's truly chilling is that the most-cited lines from the poem seem to capture the essence not just of the U.S. presidential race but of the state of politics in most Western countries. "Things fall apart/the centre cannot hold" and "The best lack all conviction/while the worst are full of passionate intensity" speak to the angry populism and political polarization that may not only put Mr. Trump in the White House but send Europe hurtling toward its ethnic nationalist past.

Story continues below advertisement

Almost everywhere in the West – Canada being a glaring exception – right-wing demagogues spewing nativist suspicion of others and left-wing populists disparaging the rich and promising free everything have leapt into the breach created by a centre constantly ceding ground.

Either the political elites who caused this breach will smarten up enough to articulate an agenda that harnesses the best elements of globalization and moderates its worst ones, giving all citizens a reason to buy into cross-border integration, or rising economic nationalism, nativism and identity politics will thrust the West into another dark period in its history. Which will it be?

The British appear increasingly likely to vote to leave the European Union on June 23 as the anti-immigration fear-mongering of the Vote Leave campaign proves no match for the common-sense arguments of the Remain forces. Leave's latest scare tactic involves warning that the (distant, if not improbable) prospect of Turkey joining the EU will see a million Turks flood into Britain.

Brexit or no Brexit, the next British election may be fought between a Conservative Party led by former London mayor Boris Johnson, who often seems to be trying to out-Trump Mr. Trump, and Labour's Jeremy Corbyn, whose election as party leader foreshadowed the rise of Bernie Sanders, the socialist Vermont senator who captured the populist zeitgeist of the American left.

Britain may now be ground zero for the populist revolt against Brussels, but hostility toward the EU is actually much higher in France. The far-right National Front wants to pull France out of the EU and ban immigration. Former president Nicolas Sarkozy has doubled down on identity politics in an attempt to get his old job back in 2017, denouncing, in a speech last week, the "tyranny of the minorities" that has imposed a "post-national ideology" on France.

France's governing Socialists, meanwhile, face a schism under an enfeebled President François Hollande. A much watered-down reform of the labour code aimed at kick-starting the job market is seen by traditional Socialist allies in the union and student movements as a betrayal, fuelling a rise of far-left parties that could annihilate centre-left candidates in the 2017 elections.

It's already happening in Spain, where the centrist Socialist opposition faces third-party status after the June 26 election. Spain has been spared the anti-immigration backlash engulfing most of its neighbours, but the surging anti-austerity upstart – Podemos, Spain's answer to Greece's Syriza – would take the country down the Greek path of resentment.

Story continues below advertisement

Centrist-party candidates got only 22 per cent of the vote in the first round of Austria's recent presidential election, with a former Green Party leader narrowly edging out Norbert Hofer of the far-right Freedom Party in the final round. A similar polarization of the electorate is happening in Germany, where support for Chancellor Angela Merkel's three-party centrist coalition has slid 17 percentage points since the 2013 election amid an anti-migrant backlash.

American historical documentary maker Ken Burns spoke of Mr. Trump in his commencement address at Stanford University, but his comments could easily apply to any number of leaders spewing similar bile across the Atlantic: "I recognize this type. He emerges everywhere in all eras … [nurturing] an incipient proto-fascism, a nativist anti-immigrant Know Nothing-ism … a political paranoia that, predictably, points fingers, always making the other wrong."

It's a dangerous moment in history, one that Yeats would recognize.