The July election has made representatives of regionalist, sovereignist, and separatist parties Spain’s new kingmakers. Comprising 39 MPs from a wide array of political parties, this influential group constitutes 11 per cent of the parliament. Its members include left- and right-wing Catalan and Basque separatists as well as other advocates of sovereignism and regionalism. With the left- and right-wing blocs both short of a majority, the election result has renewed attention to the political conflict over Catalonian independence as well as the uneasiness with which the Spanish system deals with its geographical plurality.

The nationalist movements in both Catalonia and the Basque Country are not recent. The unification of Spain only happened in the 16th century. As nation-building movements emerged throughout Europe during the 19th century, Basque and Catalan national sentiment also came to life. The independence question resurfaced in the public debate in the late 1970s when democracy was restored in Spain. After the armed Basque separatist group ETA ended its terrorist campaign in 2011, the question became one to be settled through democratic means. Today, parties that identify themselves as paving the way to independence, from both the left and the right of the political spectrum, receive two-thirds of the vote in the Basque Country – and 30 per cent in Navarra – and close to half in Catalonia.

The centre-right has traditionally represented these ambitions for independence. Their platforms brought together neoliberal economic politics that serve the interest of big capital in these two rich regions and a centrist approach open to deals with both the all-Spain centre-left PSOE and the right-wing Partido Popular. After the financial crisis of the late 2000s and as discontent with status-quo politics grew, left-wing pro-independence forces gained prominence. The Republic Left (ERC) in Catalonia currently leads the regional government, whereas Basque Country Unite (EH Bildu) recently became the biggest nationalist party across the Basque regions.

Unlike Canada and the UK, the Spanish government refuses to offer a legal and democratic pathway to independence. This stance led to the 2017 Catalonia political crisis, when the region unilaterally declared independence and the subsequent suspension of its autonomy. A return to stability has taken years, starting with the 2018 vote of no confidence in the right-wing government of Mariano Rajoy and with Pedro Sánchez becoming Spain’s prime minister with the support of Catalan independentist parties.

But Spain is not the only EU state where parties that question the national status quo have developed into key players.

On the island of Ireland, Sinn Féin has become the biggest party both in the North and South. Its rise has forced a previously unlikely coalition in the Republic of Ireland between two centrist establishment parties, to the extent that it now represents the alternative party of government. While the debate over Irish reunification will unlikely happen anytime soon, especially with the UK turning ever more to the right, the European Union needs to work towards a scenario that if a border poll happens and is favourable to reunification, then all democratic and peaceful paths towards that have all the necessary support from the Union.

Belgium is yet another case. Unlike Basque and Catalan nationalism, which exists across the entire political spectrum, Flemish nationalism today is a radical right-wing project represented by the right-wing Flemish National Alliance (NVA) and far-right Flemish Interest (Vlaams Belang). This does not make it any less legitimate – the right to self-determination is a fundamental right that does not hinge on the arguments used to defend it – but it makes the discussion fundamentally different; we are not talking about a real debate over a national project but a debate over how an exclusive and racist nationalism can take power. The rise in Flemish nationalism is thus linked to the rise of the far-right and the radicalisation of the centre-right in other European countries. Belgium’s deadlock of constant grand coalitions which leaves little room for political alternatives has further fuelled its growth. In Flanders, like in other European countries, the path forward should be that of the isolation and defeat of the far-right, together with the revitalisation of Belgian democracy through alternatives within the democratic spectrum.

Post-war Europe has been characterised not only by the longest period of peace and democracy but also by the crystallisation of the nation-state model. The homogenisation of many European countries is one of the consequences of the Second World War, whether through the genocide of large parts of the population of European Jews and Roma or the enormous amounts of population transfers seen across Central and Eastern Europe. The collapse of Yugoslavia continued the trend. Today most states of the EU are nation-states without sizable national minorities, but there are exceptions.

The centre of politics has lost its monopoly over power in Europe. In Spain, this has brought forward a progressive coalition that includes its national diversity. In Ireland, it has opened a path to a future where a government can be anchored to the left of the political spectrum. In both countries, democratic politics has defeated violence as a path to achieve national independence and showed how through democratic participation the legitimate right to self-determination can be respected. A progressive future for the European Union passes through respecting these historical learnings. In Belgium, on the other hand, the politics of secession increasingly stands in the way of progressive majorities.

The EU, as a union of people, not only of states, has a role to play. This role is a recognition that these conflicts are long-lasting and that they need to be settled through democratic debate. The EU should also – as it did during the process of German re-unification – guarantee that no change in the borders of a member-state affects EU membership. Such clarity can help avoid a repeat of the abuses of 2014, when the Scots were told that leaving the United Kingdom meant leaving the European Union.

Looking to the future, the outcome of the negotiations around the July elections in Spain remains uncertain. The next federal elections in Belgium will take place on the same day as the European election in 2024. Ireland will vote in 2025. All we can say today is that the politics of borders, referendums and flags is back.