Recently I found myself considering the possibility of a World Parliament – something like a cross between the European Parliament and the United Nations – whose members would be elected proportionally to the population of each country. What would the political makeup of such an assembly be? As far as I’m aware no-one has yet bothered to try and work it out, so I decided to give it a go.

My starting point was the Demic Atlas, which divides the world (based on 2011 data) into 66 regions of 100 million people each, plus a 67th region (covering Australia and New Zealand) of around 30 million. I assigned the 66 regions 10 seats each (3 for the smaller region) making a total of 663 seats, not far off the current UK parliament. To make things easier, where a country was split between one or more regions, I combined these together. Most of the resulting constituencies had between 10 and 50 seats, the exceptions being Australia/New Zealand and the much larger constituencies which contained India and China.

The next step was calculating the distribution of seats among parties. After leaving out countries with populations below 1 million, as they were unlikely to affect the result and therefore not worth bothering with (no offence), I set a threshold of 5% for each individual country. Parties with above 5% had their votes assigned to a constituency-wide party according to their rough ideology – more on these parties below. The votes for each overarching party were added up across the region, and then seats assigned to the parties based on the D’Hondt method. Within constituency-wide parties, seats were then assigned to individual countries by the same method.

Before we look at the results: firstly, I’m working on the basis that countries’ nationwide elections for the lower house also function as elections for the World Parliament. In this world, countries are allowed to decide their own system, and there is no requirement for proper democracy – if you want to try and figure out how China would vote in a free and fair multi-party election, be my guest. Countries which have not held nationwide elections in the past 10 years were excluded. Also, there are plenty of countries with no full results online – or at least none which are easily searchable – which means there’s a lot of ‘educated’ guesswork on my part here, especially in Africa.

With all that in mind, here’s how I reckon the seat distribution would turn out:

From left to right: Communists, Socialists, Social Democrats, Greens, Regionalists, Liberals/Centrists, Conservatives, Nationalists, Monarchists, Islamists, Others

If it were necessary to form a majority government under this system, it’s hard to see how it would be done. A grand coalition (Social Democrats + Liberals + Conservatives) would only have 320 seats, and would have to unite with one of their difficult neighbours – either the Socialists or the Nationalists. Meanwhile, a left-wing grouping (Communists + Socialists + Social Democrats) would need support from the Liberals to govern. If you’re feeling particularly adventurous you might even consider a “horseshoe coalition” of Communists, Socialists, Nationalists and Islamists, which would have a small majority, although I suspect Die Linke and Podemos at least may object to allying with the far right.

In addition, here’s a rough map (who has the time to colour in all the islands?) of the largest parties by constituency, along with the seats assigned to each constituency (grey means either there are two or more parties with the same number of seats, or that you’re looking at Antarctica). There are some obvious patterns: the high popularity of left-wing parties in Africa and Latin America (the latter partly drowned out by Brazilian conservatives); the contrasting tendency towards the right in Eurasia; and the liberal bastions of North America, the Philippines (ignore Duterte) and Iran – which at least demonstrates the limitations of such broad political groupings.

I also tried to estimate how many of these parliamentarians would be women – based on data from the Inter-Parliamentary Union – and the answer is just 147: less than a quarter. Europe and the Americas are both higher at 30%, as is Africa with 26% (which rises to 30% just by excluding Nigeria, which has 16 MWPs of which only one is a woman). However, those numbers are being dragged down by the figure for Asia – just 18.7%. Incidentally, only 24% of US Representatives are women, well below many countries which Americans might consider “less advanced”. My estimate suggests that Mexico would be sending eight women to the World Parliament, the highest number for any country apart from India and China.

Finally, let’s take a quick look at the individual parties. The Communists, which includes authoritarian socialists, are the largest grouping with 158 seats. This is almost entirely thanks to the Chinese government, though they also pop up in Africa and elsewhere in Asia.

The Social Democrats (132 seats) are the largest of the three “mainstream” parties. Most of their representation comes from Africa and India – they are weak in the Americas and the rest of Asia, and only the third-largest party in Europe (where five of their seats belong to the Labour Party). Meanwhile, the Socialists (32 seats) are almost entirely concentrated in Africa and Latin America, with only six of their seats coming from outside these regions.

With 136 seats the Nationalists (which also includes conservatives who lean closer to the far right than to the centre) are the largest force on the right, with more than half of their seats belonging to Narendra Modi’s party in India. They are also the largest party in Europe, with 14 seats in Russia and five in Italy.

The Conservatives (115 seats) are distributed fairly evenly throughout the world, although their biggest group comes from the Americas, mostly through the Republicans in the US and various parties in Brazil (incidentally, five of their seats are assigned to the UK’s Conservative Party). Elsewhere on the right are the religiously conservative Islamists with 10 seats in Sudan, Tunisia, Syria and Indonesia; the Monarchists with one seat each in Morocco and Saudi Arabia and a pro-Kurdistan independence party in Iraq, counted as a Regionalist.

Finally, the main centres of power for the Liberals (73 seats) are the US, where the Democrats hold 15 seats, and the reformist parties in Iran (fans of the Liberal Democrats will be pleased to know they’ve snuck onto the World Parliament with one seat). Our list of parties concludes with one Green in Germany, and two parties of unclear ideology in DR Congo and South Sudan.

Of course, whether parties with such different histories and policies would be willing to band together into incredibly broad groups is a different question entirely – this is purely an academic exercise. Regardless, I believe it has some interesting things to say about the distribution of political ideologies around the world – and into just how small European politics is on a global scale.

Click here for details of the constituencies.