Beware the Ides of March, Julius Caesar was warned before his fatal visit to the Roman forum on 15 March, or at least that is what Shakespeare would have us believe.

We no longer celebrate that particular religious festival, but next Wednesday will be a big day in the political and economic calendar. It will be the first test on the continent for the wave of populism sweeping through Europe: the Dutch elections. There are rumours it may well also be the day that the UK triggers Article 50, giving notice of the intention to leave the EU, though this is still dependent on parliamentary procedure. And it will be the day when the US Federal Reserve again increases interest rates, signalling the divergence in economic fortune between the US and the eurozone.

The three hang together. In the Netherlands nationalist politician Geert Wilders is consistently running either first or second in the polls after calling for the country to leave the EU. In the UK we have already made our decision to do so. And what is happening in the US is a stark reminder of the extent to which the country has had a much more positive economic experience than most of Europe since the great recession in 2009. If voters are fed up with the status quo in the US, and the choice of president suggests they are, voters in Europe have even more reason to be tetchy.

The Netherlands matters most though, because the pitch that it might leave the EU ought not to gain much support. It was one of the founding members and has done very well out of its membership. According to Eurostat, it has the highest per capita GDP of any country in the EU, bar Luxembourg and the rather special case of Ireland. It also has a relatively egalitarian society, good infrastructure, relatively low unemployment (5.3 per cent) and a successful business sector.

As it happens I have been in Amsterdam twice in the past few weeks, including a visit earlier this week talking with some business people. The message was not only one of regret about Britain’s exit, but also concern about any weakening of trade between the UK and Europe. That's to be expected, given that the Netherlands is not only one of our closest economic partners but also has broadly similar ideas about how business should be conducted (two of the largest multinationals are the Anglo-Dutch Unilever and Shell). There was inevitably a certain bewilderment at the choice UK voters had made, but that was easier to understand than the local political mood. Why should people in the calm, prosperous and stable society be starting to rebel against Europe?

Geert Wilders: 'I will never be silent'

What's going on in the Netherlands is not about economics, it is about identity. Geert Wilders’ attacks on Muslims represent his anti-immigration sentiment, as does the slogan “The Netherlands Ours Again”. But the rise of populism may have more to do with a desire to protect and respect the Dutch way than limiting immigration per se. Across the country there are hints towards this idea, focusing on the importance of Dutch food and drink, advertisements celebrating national culture, the easy egalitarian relationship between the genders, and so on.

If the EU is to hold together, and break-up is now a real possibility, it has to downplay being “European” and allow national divergence. This means accepting and celebrating patriotism, rather than seeing it as a relic of an uncomfortable past.