The European Union's founding fathers won't be spinning in their graves quite yet, but they may be starting to twitch.
A core aim of the European project launched after World War II was to rid the continent of hyper-nationalism and extremism.
Yet in this month's Greek elections an outfit called Golden Dawn, whose logo is a stylised swastika and whose members give each other the Nazi salute, picked up 7 per cent of the vote and 21 seats in parliament. The extreme right hasn't been represented in Greece's parliament since the fall of the military dictatorship in 1974.
In the first round of the French presidential election a fortnight earlier, the National Front's Marine Le Pen finished a strong third with 20 per cent.
If you add the gains made by the far left, the trend becomes more pronounced. In France anti-capitalist firebrand Jean-Louis Melanchon got 11 per cent, in Greece the Communists got 8 per cent and Syriza, a hard-left coalition containing Trotskyites and Maoists, 16 per cent.
So in both countries the vote for parties with totalitarian traditions and instincts tallied 31 per cent.
Golden Dawn and the National Front are virulently anti-immigration but, that aside, they and the far left are against the same things - big business, globalisation, austerity measures imposed by German bankers and EU bureaucrats.
While this walk on the political wild side had a touch of the childish tantrum about it - if you cut our hand-outs, we'll vote for the loonies, so there - there's also a disconcerting echo of inter-war Germany.
It's sometimes overlooked that Adolf Hitler didn't seize power in an armed takeover.
In 1928 the Nazi party had 2.6 per cent of the vote. This increased to 18 per cent in 1930. By 1932 the Nazis were the biggest party in the Reichstag and Hitler came second in the presidential election with 37 per cent. In January 1933, against a backdrop of political paralysis and backroom plotting, he was appointed Chancellor.
The catalyst for this surge in support was unemployment resulting from the 1929 crash and subsequent depression, but many historians - and Hitler himself - believed the seeds were planted during the 1923 hyperinflation when banknotes became so worthless they were used as wallpaper and the middle class lost faith in Germany's leaders and the institutions of state.
Until the Nazis changed tack to woo the big industrialists in the early 1930s, they had been stridently anti-capitalist, railing against Jewish bankers - banknotes were known as "Jew confetti" - and accusing the established parties of failing to stand up for Germany in negotiations with Britain and France over war reparations. Sound familiar?
While mob democracy shakes Europe, in the US the established order is being challenged with democracy by stealth. This month, elder statesman Richard Lugar was trounced in the Indiana Republican primary by a Tea Party-backed candidate who vowed never to compromise with the Democrats.
Lugar accused the nominee of serving the interests of hardliners who want to "cleanse" the party of anyone who strays from right-wing orthodoxies, and warned that the US was becoming "mired in dysfunction" as a result of the Tea Party's ideological opposition to constructive compromise.
A Tea Party spokesman said the message to the establishment was: "You're the servants, we're the masters: do what you're supposed to do, adhere to the Constitution, or we'll fire you."
Like all ideologues, the Tea Party demonises opponents and follows a bogus, self-justifying logic. It invokes the will of the people, yet portrays elected Democrats, notably Barack Obama who won the presidency with a clear majority, as un-American and illegitimate; it claims to revere the Constitution while ignoring the fact that the founding fathers created a system of checks and balances which demands compromise and bipartisanship.
The Tea Party is employing the old political strategy of entryism, whereby a small party, unelectable in its own right, infiltrates a larger mainstream party with a view to ultimately taking it over.
In the 1970s and 1980s, the Trotskyite organisation Militant Tendency pursued an entryist campaign against the UK Labour Party with some success.
In the end it ran afoul of the Labour Party's constitution and the trade unions' bloc vote. It also didn't help that its name identified it as an alien force: apart from the inevitable fellow travellers, UK Labour belonged to the soft, social democratic - as opposed to hard, Marxist - left.
The Tea Party is a different animal and will be harder to tame. Its name has a patriotic resonance through its association with the birth of the republic and it taps into a strain of self-righteous absolutism and suspicion of Washington that is as American as apple pie.