Daniel Hannan is an MEP for South-East England, and a journalist, author and broadcaster. His most recent book is What Next: How to Get the Best from Brexit.

Spare a thought for Stephen Harper, arguably Canada’s most successful prime minister. In his ten years in office, the quiet Albertan delivered almost everything that mainstream voters wanted.

The vast and chilly Dominion became the world’s most successful major economy, the only G7 state to come through the downturn with no downturn. At the time of the 2015 election, taxes were falling more rapidly than at any time in Canada’s history, the budget was in balance and crime rates were at a record low. Illegal immigration had been curtailed, with the result that legal immigrants were grateful, patriotic and — unusually — happy to vote for the Right. The Quebec issue had been settled, partly through a general package of devolution to all the provinces. Yet the Tories lost badly to Justin Trudeau, the well-meaning, wealthy, depilated progressive who has just been showing off his Bollywood costumes and Bhangra moves in India.

Harper has just taken over as Chairman of the International Democrat Union (IDU) – a kind of Socialist International for Rightist parties founded in 1983 by Margaret Thatcher, Ronald Reagan and Helmut Kohl. Looking around the room during the meeting in Madrid that appointed him, it struck me that several of the delegates could have asked the same question as Harper: “What else could voters have asked of us?”

Consider, for example, the man he has succeeded at the helm of the IDU, John Key of New Zealand. Key also has a pretty good claim to be his country’s finest leader. If anything, he delivered an even more striking economic miracle than Harper. When Kiwis voted last year, they had experienced economic growth in 24 of the previous 25 quarters. Yet they, too, are now run by an inexperienced but telegenic young Leftist, Jacinda Ardern of the Labour Party.

There is an asymmetry in politics. In general – not always, but often enough – Right-wing parties take over at times of slow growth and rising deficits. They are sent for precisely because voters know that they have over-indulged, and feel in need of some discipline. And so – again, in general, not always – conservatives begin the laborious process of making efficiency savings, restoring order to public finances and making the tough choices that their predecessors had deferred. Voters put up with it for as long as they feel that there is still an economic crisis. But, once the problems appear to have been largely solved, they feel they can let their belts out again and send for those nice, generous, woolly-minded progressive types. Leftist parties thus tend to begin with strong growth and balanced budgets. Only when they have blown those advantages away do voters become impatient. And so the cycle begins again.

Nothing especially new there, you might say. But the 2008 crash – and, more particularly, the decision to respond to it by bailing out wealthy bankers and bondholders – introduced a new factor. Mainstream conservative parties have been losing support to populists on both the Left and the Right. The latest polls in advance of Italy’s election this Sunday, for example, have the Five Star Movement in first place. Insurgent parties are in the lead in Sweden and Spain, and have already won in France.

In part, of course, this is a natural culling process: establishment parties are displaced by newcomers, who become establishment in their turn. The Italians even have a word – trasformismo – for the phenomenon by which formerly radical parties are drawn into centrist coalitions. That process is now happening faster than at any time since the Second World War.

Parties of the traditional Centre-Left have, if anything, been even more badly affected. Germany’s SPD is now, in some polls, third behind the Alternative for Germany. At the recent election, it secured its worst result since 1933, while the CDU got its worst result since 1949. In France, the Socialists are in fifth place. The Dutch Labour Party is in seventh place.

These things are not happening at a time of global economic contraction, quite the contrary. Indeed, the upswing has as much to do with the acceleration of the political clear-out as has the rise of social media.

For decades, voters were warned not to cross certain lines. They had to vote for acceptable parties, said the pundits and politicians, or all manner of unspecified disasters would befall them. Well, electing Donald Trump was the ultimate crossed line. The man was unsuitable for office on almost any definition. But look what has happened since he took over. The American economy is now growing at a rate of 3.2 per cent, unemployment has tumbled to 4.1 per cent and the stock exchange has broken all records. Those who used to warn against voting for Trump-like candidates (including this writer) are left looking like the man behind the curtain in the Wizard of Oz.

Unsurprisingly, our warnings no longer work. Voters might as well indulge themselves again. If Trump, why not Oprah Winfrey or Tom Hanks or Will Smith or Katy Perry? Hell, why not Jeremy Corbyn? Very suddenly, all of our isms are becoming wasms.