The traditional left's slump in weekend elections has rocked the political scene in Sweden, where Social Democrats were instrumental in putting in place the so-called "Swedish model".
"The Social Democrats no longer symbolise the Swedish model," says political scientist Stig-Björn Ljunggren.
"They've lost their magic, they don't know how to tell the story of that model anymore," the well-known commentator with left-leaning sympathies told AFP.
While overshadowed by the electoral breakthrough of the far-right, anti-immigrant Sweden Democrats, the Social Democrats' catastrophic electoral performance represented a no less spectacular upset in Swedish politics.
Sweden's governing party for most of its modern history, the Social Democrats in Sunday's vote obtained their worst score since 1914. The Swedish press called it "the end of an era" for a party now "just like any other one."
"For whoever grew up in Sweden in the second half of the 20th century, power was almost synonymous with one political movement: social democracy," leading daily Dagens Nyheter (DN) wrote in its post-election editorial.
Long stretches of power by some Social Democrat prime ministers look more like reigns than political mandates, such as the 23 years of Tage Erlander (1946-1969) or the 11 years of Olof Palme (1969-1976 and 1982-1986), whose assassination traumatised the country.
Founded in 1889, the Social Democrat party has governed Sweden for more than 80 percent of the time since 1932.
Up until the mid-1990s, the Social Democrats would routinely garner around 45 percent of votes. The party won 30.9 percent of the vote on Sunday, five percentage points down from its 2006 result, considered at the time a political disaster.
"They have to find a new identity," Peter Wolodarski, the head of the political section of Dagens Nyheter, told AFP.
"They have to look back on their own history to see why they were so popular in Sweden," he said.
When the Social Democrat party was founded, Sweden was one of the poorest countries in Europe, and more than a quarter of its population sought relief from poverty across the Atlantic.
By basing itself on the already in place supportive and egalitarian communities of Nordic Protestantism, the Social Democrats quickly became a major force.
In a few decades, the party contributed to turning Sweden into one of the world's richest -- and most egalitarian -- countries.
"The biggest reason (for their success) is that they were not only popular among the workers, but also among the middle class," Wolodarski said.
"But that is no longer the case," adds commentator Ljunggren.
The move towards the centre of Prime Minister Fredrik Reinfeldt's Moderate Party, which is now inching up to the Social Democrats as the country's largest party, cost the socialists a large chunk of the middle class vote, both experts agree.
Reinfeldt's centre-right coalition won Sunday's vote although it fell short of an absolute majority in parliament.
Observers also say that the Social Democrats electoral alliance with the Greens and the former communist Left also clouded the electorate.
Sweden seems to be on the path of neighbouring Denmark, which was also a longtime social democrat bastion, but since 2001 has been governed by the centre-right with the support of the far-right in parliament.
On Wednesday the Social Democrats' top brass are to meet to analyse the reasons for their electoral debacle. Some have blamed their leader, Mona Sahlin, who has said she will stay on despite failing to become Sweden's first woman prime minister.
"She might be part of the problem. But it is certain that she is not the only problem," Ljunggren says.