(CNN) The trouble with democracy is that it works. Generally people get what they want.

But what if electorates vote for politicians who don't care for democracy or don't understand its values? Who steps in to keep democracy on course?

You might think the answer would be the electorate, but you may be wrong. Now, democracy could be on the verge of a "Catch 22" moment, snagged by its own logic.

A wave of populism is sweeping through the approximately 2 billion or so voters lucky enough to enjoy democracy's freedoms, electing leaders reluctant to cherish its values.

Democracy relies on trust and everyone playing by the same rules, not a disposable concept, to be discarded once it becomes inconvenient.

This week Donald Trump suggested he might overturn the US constitution's two-term limit for presidents "if things keep going like they're going -- we'll go and we'll do what we have to do. We'll do a three and a four and a five."

Most likely he was joking, but US Democrats are raising concerns about Trump's resistance to democracy's finer points, specifically his job as president to work with politicians who don't share his views.

His staged tantrum, abruptly ending a meeting with House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer insisting he won't work across the aisle unless Democrats drop their (legal and constitutional) investigations of him is not the way American democracy was designed to work.

As the world's most powerful democracy and leader of many global trends what happens in the US matters to the rest of the world.

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Populism's ugly past

Over the past few days, India, the world's largest democracy handed a landslide second term to populist nationalist Narendra Modi . In the European Union's 28 countries, voting is taking place this weekend in EU parliamentary elections, in which populists were predicted to increase their representation at the expense of traditional parties.

Modi's massive victory scored him a rockstar reception at his party HQ.

A cult of personality is now pushing aside conventional politicians, with voters fixating on faces and names, less so on policies.

Populist politicians jostle pop singers and reality TV stars for public attention, so it's little surprise they should pop up as presidents: not just with Trump but in, of all places, Ukraine where comedian Volodymyr Zelensky morphed through one of his TV characters, to cult hero, to the country's top job.

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But the rosy image of today's populists today belies an ugly past.

In Europe, populists of the nationalist variety have a history of shunning democratic values. Adolf Hitler -- the most notorious example -- was enabled by the electorate; in turn he enabled them to indulge their basest nationalist instincts, resulting in the deaths of tens of millions in the Holocaust and in combat.

Worryingly, what India shares with Europe is a rise in attacks on the "other." Under Modi's Hindu nationalist BJP, party attacks on Muslims have increased. And in the UK, where Brexit is the cause célèbre of populist politicians the world over, attacks on minorities have increased.

Populism is now the main ticket to power, in a way it never was a few decades ago; indeed it's challenging the fundamental understanding of how democracy works.

Brexit is a case in point: although the scale of the victory was narrow -- 52% of votes cast were for leave, while 48% were for remain -- the populists would have the minority accept whatever the majority wants. Traditional democrats would seek to bridge divides.

My way or the highway is on the rise, and so are divisions, in what may become democracies biggest challenge in decades.

Natural bedfellows

In the weeks before the EU elections, Europe's populists achieved what they never succeeded before, by campaigning together.

There were many catalysts for this, not least Trump's former alt-right advisor Steve Bannon, who has been touring Europe over the past year or so, pushing the myriad populists toward unity.

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It's not been an easy task: most are nationalists, so by definition not natural bedfellows with each other, but Bannon's corralling has upped their clout, and staying power.

Where they easily align is over immigration. Italy's populist deputy PM Matteo Salvini rose to power because his country has been inundated with refugees fleeing poverty, persecution and war in North Africa. Meanwhile the EU's interminable bureaucracy failed to supply meaningful help and a solution.

In the weeks before the EU election, Salvini went on the campaign trail with other prominent populists, among them Marine Le Pen of France, and Geert Wilders from the Netherlands.

He failed to convince Hungary's hard core populist Viktor Orban and the UK's Nigel Farage to join him in his big tent, but in the EU Parliament, their acolytes will likely become cozier together over its next five-year term.

They won't be the majority, but they will be the disruptors, aiming to upend the old order and replace it with theirs.

The "Catch 22" is that it would be undemocratic to turf them out, but are they ready to play by the same rules?