Imagine one day waking up only to discover that you are not who you had been certain you had been all your life. Imagine one day having all your certainties shattered. Barnaby Joyce had this precise experience this week, and this is why he deserves our sympathy. The deputy PM of Australia should be still in shock, because what he found out about himself should be shaking him to his core of existence. He is a dual national. He is a New Zealand citizen. He’s not all-Australian. Imagine being the leader of the ‘National’ party and have your own nationality questioned. Poor Barnaby Joyce, with your red face and Akubra hat and complete lack of filter, you living incarnation of rural Australia, what is left of you, if you’re deprived of your Aussie-ness?

The question is much broader and should worry every Australian. Because if we learnt anything from the deputy PM’s ordeals, is precisely this: If Barnaby Joyce cannot be a true-blue, non-debatable, no-questions-asked Australian, then nobody can claim to be. In its coverage of the issue The Australian featured one of Barnaby Joyce’s friends saying that he is ‘as Aussie as they come’. In fact, he has made a political career out of this, of himself being a ‘true Aussie’ – well, not as ‘true’ as the people who have been living here for 50,000 years or so, but you get the picture. Being born in Tamworth, he had every right to hold this opinion of himself and be genuinely stunned to hear that he is a ‘Kiwi’.

And if anyone is interested in what a true Aussie is, they should look no further than the way the deputy PM explained how he ended up with the New Zealand nationality, bequeathed to him (under New Zealand laws) by his father, who came to Australia in 1947, one year before the notion of a thing such as ‘New Zealand nationality’ even existed. “My father was born a British subject”, said Barnaby Joyce, offering a rare glimpse on the true nature of nationality.

Yes, a ‘True Aussie’ is someone who was previously a subject of the British Empire. This may seem like a contradiction, but it is not. Because, in fact, a great number of countries in the world became sovereign states when the empire that contained them disintegrated, and most nations in the world were once part of larger, multinational empires. Australians and New Zealanders, as well as the other colonies of the British Empire, came late to the party; the rest of us went through all this a century earlier. Been there, done that. Europeans know what it means seeing an Empire collapse and new states being created in the name of nations. See, the idea of a ‘national state’ is a fairly new one, emerging in the 18th and 19th centuries, after revolutions, movements, monumental shifts in societal structures.

The constitutions of the national states emerging after the collapse of the Empires needed to offer legal definition of the people. Most based their idea of citizenship to their idea of nationality. What this meant was that, for a country to have citizens, it would need to have people with a common national identity first.

Greece is a great example of this. Coming out of a revolutionary war, the new country needed a constitution to set the rules. One of the first rules was the definition of Greek citizen – this proved to be easy: in the first constitution of the Hellenic State, Greek citizens were considered all who were Christians. It was the most practical thing to do, in a country created from a wide array of nationalities – from Vlachs and Pomaks to Romani, all who fought against the Ottoman rule needed to be counted along with the Greek, with which they shared their religion. The fact that a significant part of the population were Greek, but Muslim, complicated things a bit, but soon they converted, solving the problem. Other national identities were harder to built. In Australia’s case, it took the slaughter at Gallipoli to galvanise the nation.

So the idea of national purity, as a basis for citizenship is as old and as flawed as most modern states are. For most countries in the world, these are just legal technicalities. For others, it becomes part of their national narrative. For Greece, this means being unable to separate the church from the state. For Australia, to see a series of senators proven to be ineligible under the constitution, or to make the issue of citizenship a central part of national policy. We live in a complex world, where people have been moving in various directions for centuries. We should accept the fact that national purity does not exist, that we’re all a mix and match of histories and cultures, and move on.

As for Barnaby Joyce, even as a New Zealander, he still remains Aussie as sausage sizzle – and there’s one thing that sausage and nationality have in common. Nobody wants to know how they are fabricated.