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Readers of Today's WorldView are certainly aware of the prevailing theme of the past year in global politics: the stunning ascendancy of right-wing populism in various corners of the West, including the United States. But we've discussed the other side of the story a bit less.

On both sides of the Atlantic, the liberal establishment and social-democratic parties are reeling. Their decline and disarray in some places seems almost terminal.

There has been a sense of crisis for quite some time, even before Britain voted to quit the European Union or President Trump, breathing nationalist fire, upset the apple cart in Washington. In 2016, European social-democratic parties lost 12 out of 18 national elections. In the United States, Trump's election cast the Democratic Party — particularly in its cautious, centrist Clintonite form — into the wilderness, with Republicans dominant in both Congress and state-level governments across the country.

The center-left's pain continued last week in Britain. A by-election in Copeland, a constituency near the Scottish border, was won by a Conservative candidate for the first time in more than eight decades. It was also the first time in 35 years that a governing party in Britain wrested control of a seat from the opposition between general elections.

Once the natural home of Britain's working class, the Labour Party has seen disaffected voters lured away by anti-immigrant platforms. Its embattled leader, leftist Jeremy Corbyn, is fighting a pitched battle with the moderate factions that have controlled the party since the ascent of Tony Blair.

"Labour continues to be torn ... between members of a working-class base who want out of the E.U. and a young, urban and progressive contingent that favors staying in," reported my colleague Griff Witte last week. "Corbyn has alienated both factions — reluctantly favoring remain last June and putting up only halfhearted resistance to May’s plans."

All the while, polling shows Labour lagging far behind the Conservatives. Some analysts even suggest that Britain under Conservative Prime Minister Theresa May is turning into a one-party state, with May more concerned about internal divisions on the right than the challenge posed by the left.

If the left and the center-left don’t get their act together, then we’re looking at a period of very unstable right-wing hegemony,” said Alex Callinicos, a European studies professor at King’s College London, in an interview with my colleagues last year. Social-democratic parties may have helped fashion Europe's welfare states and enshrined workers' rights, but in recent years, many have become synonymous with the corporatized, faceless establishment.

"The merger of traditional social democracy with neoliberalism and globalized free-market policies has fallen apart in fairly disastrous fashion," said Callinicos.

The situation is also dire for the center-left in the Netherlands, which holds elections this month. The focus there is on the contest between far-right, anti-Muslim candidate Geert Wilders and the country's center-right, classically "liberal" Prime Minister Mark Rutte.

The Dutch Labor party, which allied itself with Rutte in a coalition government, seems irrelevant. It appears to be hemorrhaging voters to both the anti-immigrant far right and to parties further to the left. From commanding the second-biggest block of seats in the Dutch parliament, Labor may fall as low as seventh.

Lodewijk Asscher, the Labor party leader and deputy prime minister, laments the center-left's inability to hold onto its working-class base. "They have felt most of the crisis," said Asscher to Politico, referring to the toll of the 2008 global financial crisis. "We have to find a solution for that, rather than telling them it’s all somebody else’s fault."

But the politics of scapegoating and grievance have been well-marshaled by the far right in both the Netherlands and France, which holds its presidential election in April.

French President Francois Hollande, an unpopular Socialist, has been a lame-duck leader for months. The French left, divided into a constellation of competing personalities and interests, will  likely not be able to rival the bids of far-right leader Marine Le Pen, centrist Emmanuel Macron or even the center-right's Francois Fillon, who, despite being saddled with allegations of corruption, still commands greater support than any leftist candidate.

Even in countries without ascendant far-right movements, such as Spain and Italy, the traditional center-left is hobbled by infighting and defections.

The solution, argue some politicians, is a return to the core strengths of left-leaning parties. "The best thing to do is to fight our own battle — for social rights, solidarity and equality," wrote Sergei Stanishev, president of the Party of European Socialists, a center-left bloc in the European parliament. "This is our winning strategy and this is where we should aim our powerful left punch."

But in an age of cultural anxieties, austerity and terror alerts, far-right populists offer a more intoxicating brew, particularly as detachment grows between working-class, rural voters and urban elites.

"It is nonsense to suggest that the moderate European left is a political carcass," wrote Tony Barber of the Financial Times. "But its electorate is deeply split. One side consists of less well-off voters with conservative social values who feel under siege from E.U. policies and globalization. The other consists of affluent cosmopolitan liberals who like the E.U. and benefit from an open world."

There are still possibilities for center-left success in Europe this year. In France, Macron, a former minister in Hollande's government running as an independent outsider, stands a good chance of winning the presidency; in Germany, the emergence of center-left leader Martin Schultz is forcing German Chancellor Angela Merkel — styled now as the guardian of the liberal order — to look over her left shoulder for the first time in years.

If center-left forces "do respectably in France and Germany," writes Bloomberg View's Leonid Bershidsky, "a socialist-leaning, and probably more united, Europe will square off against a nationalist-populist U.S." Or, if their victories offer Democrats any inspiration, the center-left's resurgence could come on both sides of the Atlantic.

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