I write this from London, where Donald Trump is only the second biggest story. But it's an instructive vantage point from which to watch the Republican odyssey. In one sense, it's about the furthest place you can imagine from Trump's unvarnished parochialism. Trump probably sounds foreign to anyone not in his thrall: like the themes are vaguely familiar but the language isn't.
But in London – a thoroughly global city – Trump inhabits a completely different planet. He's not merely talking strangely – something of a feat in a city that's home to more than 300 languages – he's expressing inconceivable thoughts. Mexicans (or Arabs or Asians) aren't remarkable here. London doesn't build walls. It's boundless.
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But in another sense, this is the kind of city that made Trump. Its increasing number of kinky skyscrapers stand as testaments to global capital: shiny, innovative. London has always had a sense of old money – how could it not with its parade of palaces and castles? Now it's just money. Money with no apparent local history, and certainly no need for it. The kind of money that is its own justification. Money that, to riff on a central Trump theme, wins.
But all that winning creates losers. London is now systematically expelling its own people because, with the fabulously wealthy parking their money there, it's an increasingly rare Londoner who can even afford to rent. Soon we'll see schools unable to find teachers because no one on a teacher's salary can live close enough to work there. Turns out this glorious, boundless world has boundaries after all. It erects its walls, too, just not with Trump's bellicosity.
If you're walled out in America, there's a good chance you're presently waving Trump placards. That's not merely an American phenomenon so much as a quintessentially American expression of a global one. To see that we need only glance at the biggest story in these parts: Britain's serious flirtation with leaving the European Union.
That decision will be made by a popular vote in June, and it suddenly seems a close-run thing. And that's no small matter because, while Euroscepticism has always had its place in British politics, it has never been the orthodoxy.
There are many reasons for the political change – including David Cameron's struggle to control his own party and the rise of the UK Independence Party – but it is perhaps most revealing to listen to the way pro-European voices tend to speak as they explain what's at stake. It's the language of economic opportunity, of radical mobility.
Probe a little and you'll hear arguments about how wonderful it is to be able to relocate, without much of a thought, to take up a job – or indeed buy property – in Spain. Then France or, I dunno, Portugal, before whizzing back to London. Listening to this it sounds fantastically enticing. But then, I've just whizzed to London myself. It's roughly then that it dawns on me.
These arguments all belong to the elite. It's an experience of Europe that simply doesn't ring true to the struggling classes. It's hard to value the opportunity to up sticks for the continent when it's not one that applies to you. Not everyone surveys Europe and sees a field of dreams.
Millions are more likely to see a source of competition, for jobs, for houses, for everything. That's why the ugly side of this, centred on the influx of Eastern European migrants, is never far from the surface of this debate. It's not cogent – Britain's terrible housing crisis is a familiar story of undersupply and hyperactive investors, not swooping Poles – but it's a powerful enough image to stick.
The themes here are closer to Trump than might immediately appear. The incessant media focus on Trump's outrages masks the fact that he's also running a seriously protectionist campaign: ironically suspicious of free trade and protective of an American underclass for whom the triumphs of capitalism seem only to flow elsewhere. It's not arguing that the system never works. It's that it always works for the same people: the establishment who write the laws for the benefits of their friends and themselves. If that's not you, chances are you feel thoroughly disempowered, whether you live in the world's most powerful nation or not.
So, "Make America Great Again". Or to cast it in Brexit language, reclaim Britain's sovereignty, even freedom. In each case, it's really a promise of power and control. Even if those promises are completely overblown and doomed to fail (and I think they are) it's hard to deny their attraction.
It's also an explicit rejection of the gospel of the last 30 years. It's a long time since we've seen mass movements in domestic politics gather around something quite that radical.
That's what makes this a big moment: the sense that everything right now is up for question; that elite wisdom may no longer count as wisdom at all. Trump's politics of scandal and political incorrectness works because it's really a war on orthodoxy. And if Britain can leave the EU, perhaps it will be a sign that we're in the age of the heretic.
Waleed Aly is a Fairfax Media columnist and a lecturer in politics at Monash University.