PARIS (Reuters) - Italian comic-turned-activist Beppe Grillo has blazed a trail for populist political movements around Europe by taking his Five Star Movement (M5S) from obscurity to become Italy's largest party in its first general election campaign.
Grillo's stunning success in turning a fringe protest group into a national force while refusing to be interviewed on television or debate with mainstream politicians may be studied by political scientists and campaign operatives for years.
Populists hostile to the euro or to immigration have ridden a wave of anger over austerity, recession and unemployment to make inroads from the Netherlands to France, Finland and Greece since the financial crisis began in 2008.
But none has upended national politics as suddenly as the 64-year-old Grillo, a self-made millionaire satirist.
His spectacular rise highlights the threat to center-right and center-left parties of government around Europe that are involved in implementing unpopular austerity policies and structural economic reforms.
Grillo's unique combination of grassroots organization, personal charisma, rock-star-style road tour, Internet savvy and use of social media confounded pundits and stunned an elderly political class when M5S grabbed 26 percent of the vote.
His central theme is to denounce the Italy's political and business elite as corrupt and over-privileged.
The new-age movement of political novices, which advocates sweeping electoral reform, clean government and environmental causes, seized the balance of power in the Senate, making it hard for any party to form a stable government.
"By standing on an anti-establishment platform and using modern communications, (Grillo) has combined medium and message to create a genuinely novel type of movement," Britain's Demos think-tank said in a report.
"Grillo's remarkable success shows the effectiveness of communicating and organizing through the Internet - and the potential that has to speak directly to millions of people, especially those who are disenchanted with existing political structures," said the study of his Facebook followers commissioned by the Open Society Institute.
Historically, revolutionaries have often exploited new technology to propagate their message and outwit flat-footed authorities. Martin Luther used the printing press to challenge the Roman Catholic church's monopoly on the scriptures.
In 1978, Ayatollah Ruhollah Khomeini's anti-Shah sermons calling for an Islamic Revolution, dictated by telephone from exile in Iraq and France, were smuggled around Iran on mass-replicated audio cassettes.
The fax machine played a key role in the 1987 Palestinian uprising, relaying instructions from underground leaders around towns, refugee camps and villages in the occupied West Bank and Gaza Strip cut off by Israeli military blockades.
Radio and television broadcasts from the West helped bring about the fall of the Berlin Wall and communist rule in eastern Europe and the Soviet Union in 1989-91.
Grillo's social media campaign mirrors tactics used by Arab democracy activists in 2011 to mount protest movements that swept veteran autocrats from power in Tunisia and Egypt.
M5S's policy statements are issued via Grillo's blog, the most widely read in Italy according to 'BlogItalia' rankings.
His Facebook page has nearly 1.3 million fans, more than twice the number of center-right former Prime Minister Silvio Berlusconi and roughly 10 times the following of center-left leader Pier Luigi Bersani and outgoing technocrat Prime Minister Mario Monti. He also has a million followers on Twitter.
Grillo shunned the traditional media by choice, accusing them of being in thrall to corrupt politicians and big business.
Instead, he criss-crossed Italy in a camper van on a "Tsunami Tour" of 77 public rallies in 38 days, drawing hundreds of thousands to town squares, while countless thousands more watched live webcasts of his hoarse-voiced harangues.
His success in galvanizing alienated voters, especially the young, wrongfooted pollsters who had credited M5S with just 16 percent in the last published surveys two weeks before the election.
While austerity has driven voters towards the radical fringe across much of Europe, in most countries, protest parties have little prospect of winning national power.
In Greece, however, the radical leftist SYRIZA party, which opposed an EU-IMF bailout, almost beat the center-right New Democracy party of Prime Minister Antonis Samaras before voters stepped back from the brink in a second election last June.
The ultra-nationalist Golden Dawn, branded neo-Nazi by critics for its black-uniformed activists and muscular anti-immigrant crusading, won 7 percent in that election and now polls more than 10 percent, putting it in third place.
Although another election is not due until 2016, Brussels policymakers' nightmare is that Samaras' fragile coalition falls apart over austerity measures, forcing an early poll that could open the door to radical forces.
In Spain, corruption scandals, a long recession and high unemployment have soured the public mood and voters are turning increasingly toward smaller parties to express their disgust with the center-right People's Party and the Socialists.
Yet politicians and pollsters do not see an extreme fragmentation that would break down the country's dominant two-party system and lead to Italian-style uncertainty.
The latest Metroscopia poll shows that if elections were held now, Prime Minister Mariano Rajoy's center-right Popular Party would take 24.3 percent, far from its absolute majority in 2011, and the opposition Socialists would get 23 percent.
The ex-Communist United Left has risen to 15.4 percent, more than twice its 2011 result and the centrist Union for Progress and Democracy has doubled its score to 10.0 percent.
In wealthier northern Europe, where the economic crisis has not bitten so hard but resentment of bailouts for south European countries is strong, populists may have peaked for now.
The two mainstream pro-European parties won a surprisingly clear general election victory in the Netherlands in September, while anti-euro radicals on the right and far-left fell back after riding high in the polls early in the campaign.
Voters punished Geert Wilders' anti-Islam Freedom Party, which had held the balance of power before the vote and imposed some of its anti-immigration agenda, for bringing the government down and opposing European Union membership.
In Germany, the Pirates Party, which campaigns for Internet freedom, looks to be running out of steam after a string of regional gains. It is polling well below the 5 percent threshold for entering parliament in September's general election.
The anti-bailout Finns Party scored less well in local elections last year after its general election surge in 2011.
While Europe's populists are moving away from the limelight on some national stages, they may move towards it in next year's European Parliament elections, where an expected low turnout will give protest votes greater impact.
Writing by Paul Taylor; editing by Philippa Fletcher