Nothing can bring people together quite like football. You only need to look at the fervour bring whipping in England at the unexpected success at the World Cup.

Gareth Southgate and his men have done more than anyone to bring the country together, at a time when deep political divisions seem to remain firmly entrenched.

Whilst there are always those who will take things too far, the nationalistic feelings expressed are only a little less innocent than the naïve belief that it really is coming home.

Yet for England’s semi-final opponents, Croatia, football and nationalism are intrinsically linked, and whilst that can take the form of simply being proud of how the football team are representing their national on the international stage, national sentiments can take a more dangerous form.

To understand why footballing success has such an impact on the psyche of the nation, we have to go back to the birth of the modern-day Croatian state.

Croatia’s struggle for independence

Croatia had been a part of Yugoslavia, a national that united the South Slavic people of the Balkan region, for much of the 20th century. For much of the post-war period, the country was held together by Tito, but his death in 1980 preluded the rising of ethnic tensions within and between the various republics.

This process was accelerated by the collapse of communism across Europe in the late 1980s and early 1990s. Many in Croatia, and the other republics, felt that the balance of power of the state was unfairly tilted towards Serbia, and as the 1990s began they were increasingly willing to express this.

One of their outlets for these feelings was football. The rivalry between Croatia’s leading club, Dinamo Zagreb, and the Serbian Red Star Belgrede was one of the fiercest in Yugoslavia. Matters came to a head in May 1991, when a game between the two at the Stadion Maksimir in Zagreb broke out into the violence.

Dinamo captain Zvonimir Boban infamously kicked a police officer attacking a Dinamo fan, and was lauded as a national hero for doing so, with the police often seen as apparatus of the Serbian ‘elite’. Significantly, that match came just two weeks after the nationalist Franjo Tuđman was elected as Croatian president. Croatia would declare independence just over a year later.

As Jonathan Wilson refers to in Behind the Curtain, both sets of fans – the Deljie of Red Star and the Bad Blue Boys of Dinamo – believe they fought the first battle of the war that day, and many of the ultras fought on the front line of the wars to follow. The Dinamo ultras also willingly aligned themselves with Tu­đman’s party, the Croatian Democratic Union (Hrvatska demokratska zajednica or HDZ), showing the close link between fan groups and nationalist ideology.

Whilst the atrocities committed in Bosnia are better known in the West, the Croatian War was equally brutal, with the town of Vukovar razed to the ground and its people massacred, whilst Dubrovnik was laid under siege by Serb forces. Ultimately, the Croatians pushed them back and gained control of their ‘own’ land, but the animosity between the two now-independent nationals still holds firm today.

Politics and the success of the national team

There is a problematic feature in Croatian nationalism, specifically its alignment with the imagery of the Ustaše, the fascist group given power in Croatia during the Second World War by the Nazis.

Part of their symbolism was a version the šahovnica, the red-and-white-chequered coat of arms that is used today on the Croatian flag and by its national football team, both as its logo and as the inspiration for their famous red-and-white shirts. It must be noted though that the shield’s origins go back many centuries, whilst the version used today has a red square in the top left-hand corner, rather than a white one as the Ustaše used inside its U-shaped badge.

Whilst the links between Croatian nationalism and the far-right can remain a disturbing issue to this day, as Serbians, especially, would be quick to point out, the red-and-white imagery is very much normalised in the national consciousness. However the choice of the newly-formed national team to proudly display its national identity shows how strong these feelings were at the time of independence.

Tuđman himself was also a keen football follower, and a Dinamo fan, although he had also had a spell as chairman of the other major Belgrade, FK Partizan, but he was also well aware of football’s potential as a propaganda tool to promote his fledgling nation.

Dinamo themselves were renamed as HAŠK Građanski at his request in 1991, recalling the names of two clubs that merged to form the club in 1945, with Dinamo seen as a ‘communist’ name. They were later renamed Croatia Zagreb, under which they would represent the county in two UEFA Champions League group stages campaigns in the late 90s. They would revert to Dinamo, as the fans had continued to call them, after Tuđman’s death in 2000.

Perhaps even he couldn’t have dreamed about the impact the national team could have, though, with the country laying claim to a significant number of a golden generation of Yugoslav players that emerged in the years leading up to its disintegration, including several members of the 1987 FIFA World Youth Championship winning squad.

Having joined UEFA too late to enter qualifying for the 1994 World Cup, they would immediately qualify for their first international tournament, UEFA Euro 1996, and would reach the quarter-finals in England, before an even more memorable run to the semi-finals in 1998, which saw them beat Germany 3-0 in the quarter-finals and Davor Šuker win the Golden Boot.

Tuđman would happily fraternise with the squad, both publicly and privately, as revealed by defender Slavan Bilić, later the national team coach, speaking to Wilson in 2005. “Tuđman said to us that we like ambassadors for Croatia,” he revealed, adding that the two had even had lunch together once, calling it “one of the best memories of my life,” whilst also adding his indifference to the significance of the president’s relationship with his players.

Miroslav Blasević, the extravagant coach that led Croatia to its first two major tournaments, said that his players had been “full of a sense of patriotism,” and that “one of the biggest advantages Croatia has in sport is that patriotic feeling.” Whilst others, including Bilić, have downplayed the nationalism element, there is no doubt it was a key factor. And the success of the team helped to give the country its place in the world, and that cannot be underestimated.

Dark forces aside, the team inspires the nation again

Fast forward 20 years, and the lure of the team and its success is no less significant to politicians. Current president Kolinda Grabar-Kitarović certainly made sure she was noticed when travelling to Sochi to support the team in their quarter-final against Russia on Saturday, wearing a Croatian kit in the stands during the game and celebrating the team afterwards. This is not unique to Croatia though - Angela Merkel was also keen to be seen with Germany's 2014 champions.

Meanwhile, fans on all sides are happy to see the war of old reignited in the name of football, with meetings between Croatia and Serbia still much dreaded amongst authorities and a chance to reopen wounds that have never healed. It will not be lost on Croatian supporters that, not for the first time, their side has convincingly out-performed their Serbian counterparts in this World Cup, with their rivals failing to make it out of the group.

Whilst Balkans tensions were most notably played out at the World Cup when Serbia were beaten by Switzerland, for whom Granit Xhaka and Xherdan Shaqiri, both of Kosovar-Albanian descent, scored, there was mild controversy when Croatia defender Dejan Lovren filmed himself signing a song that uses the phrase “za dom Spremni” (“ready for home”) that was used as a greeting by the Ustaše, following the win over Argentina.

Far-right sympathies often find themselves being expressed by Croatia fans, and Josip Šimunić was fined and banned after leading fans in a chant of the same phrase after the team qualified for the last World Cup with a win against Iceland. That was his final game for his country, but he was still able to become assistant to former coach Ante Čačić.

Whilst it is a minority of Croatians who may share these sympathies, with the world as it is at the moment, it is important to understand these undercurrents. As journalist Krsto Lazarevic wrote on Deutsche Welle, “fascism is still acceptable to Croatian football fans today.” It should be remembered to that the current generation of players grew up during and after the war.

It is also relevant to note that going into the tournament in Russia, there was an indifference, perhaps even a dislike, of the Croatia team amongst a significant number of supporters. This is largely related to a major corruption scandal surrounding the controversial figure of Zdravko Mamić.

Mamić has been convicted of fraud in Croatia for illegal payments to himself whilst acting as president of Dinamo Zagreb and as an agent for some of its leading players. Amongst those are Lovren and current national skipper Luka Modrić, who have both been ostracised for their failure to give compelling evidence against Mamić during his trial. Modrić has played a major part in their run to the semi-finals, but even if he lifts the World Cup trophy on Sunday, it will do little to win back many in his home country.

Nevertheless, the on-the-pitch success in the past few weeks has papered over those cracks and others, for the time being at least. The nation appears to be as gripped to the World Cup as we are in England, with many scrambling what money they have to make it to see their side in the latter stages of the competition.

The issues haven’t gone away though. Hardcore football fans still express these concerns but they are “out-numbered” and “the nationalist frenzy has taken over,” according to writer Dario Brentin, speaking on Twitter. “Difficult questions get side-lined & atmosphere of patriotism is making it more & more difficult to express critique without being ‘unpatriotic’,” he continued.

Just as in other parts of the former Yugoslavia, Croatia’s footballing success is entwined with their nationhood as a legacy of the part football played in the war and in helping the region to recover, as seen with Croatia’s success in France 20 years ago. A World Cup win would make this link even more inseparable, even if the stains of the far-right elements and the Mamić affair will not go away.