It is hard to see how the vitriol will subside this side of Turkey’s vote, but for the president that is a problem for another day

It is a mark of Turkey’s abandonment of its once pre-eminent diplomatic priority – membership of the European Union – that Recep Tayyip Erdoğan has been so ready to wade into a vitriolic diplomatic row with Europe.

The Turkish president has sparked fury from Angela Merkel and Mark Rutte, two of the EU’s most liberal leaders, with his evocation of nazism and Islamophobia. For good measure he has also reminded Turks of the Dutch role in the Srebrenica massacre.

Turkey bans Dutch ambassador as diplomatic crisis escalates Read more

The external damage may be long-term, but Erdoğan seems to be willing to shrug it off. His priorities right now are entirely domestic and short-term.

Involved in a self-imposed battle for political survival, Erdoğan has staked all on winning a referendum set for 16 April in which he seeks to transform Turkey from a parliamentary system to an executive presidency. A yes vote would give him autocratic powers that were only this week condemned as excessive by a Council of Europe inquiry.

Ever since last summer’s military coup attempt, Erdoğan, skilful politician that he is, has exploited continuing threats to the state – real and imagined – to persuade the Turkish people that it needs a different kind of democracy. Bombings by Islamic State and the separatist Kurdistan Workers’ party (PKK), as well as the network of so-called Gülenists – whom Erdoğan blames for the attempted putsch – have provided him with a ready trilogy of wreckers. It is partly their existence, he argues, which requires the country to impose a more powerful figure at the helm.

Launching his campaign in January, Erdoğan oozed confidence. “It is too soon to share the results of the polls we have right now,” he said, “but let me tell you this for now: we see that our people have warmed up to the idea of a partisan president. Indeed, if we were not sure of this, we would not have embarked on this business [supporting the referendum].”

His confidence was bolstered by the knowledge that he had a massive propaganda machine behind him with one message: “For a strong Turkey, vote yes.”

In such circumstances it might be expected that Erdoğan’s path to an imperial presidency would hardly be burdensome. But polls reveal that is not the case.

Though fluctuating, they have broadly shown that Turkish voters are divided, with about 40% in favour of the changes, 40% against and the remaining 20% undecided. Defeat would be unthinkable – a humiliation for a man who feels he has never been adequately thanked by Europe for all Turkey’s efforts in giving safe harbour to millions of Syrian refugees.

What are Turks voting on in the referendum? Turkey goes to the polls on 16 April to vote on constitutional amendments that would transform the country from a parliamentary democracy into a presidential system. The referendum could bring about arguably the most significant political development since the Turkish republic was declared in 1923: under the new system, President Erdoğan will be able to stand in two more election cycles, meaning he could govern as a powerful head of state until 2029. The president's supporters say the new system will make Turkey safer and stronger. Opponents fear it will usher in an era of authoritarian one-man rule.

The tightness of the campaign made the ruling Justice and Development party (AKP) look at the pool of 4 million ethnic Turks residing in Europe – many of whom are dual citizens with a right to vote. Party chiefs had reason to believe Turks in Germany were pro-Erdoğan: in November 2015, when the Turkish people gave Erdoğan his latest mandate in national elections, the AKP’s support among Turkish voters in Germany 60% – 10% higher than at home.

The Turkish authorities argue it is normal for politicians to travel abroad while fishing for votes in the expatriate pool. Only last month Emmanuel Macron, a French presidential candidate, was in London wooing Britain-based French voters.

Turkey sees the ban on its politicians holding rallies – something that started in Germany at a local level, but was supported by Austria, and then the Netherlands – as a sign that Islamophobes have won the argument in Europe.

Yet as soon as the first German ban was imposed, the AKP immediately took the denunciatory rhetoric and threat of reprisals to the most emotive level. It portrayed Turkey and the yes campaign as the victims of a conspiracy. Justice minister Bekir Bozdağ railed against the Germans’ “past illness” in the same breath as condemning a supposedly “fascist practice”. Turkey’s EU minister, Ömer Çelik, accused the Austrians of “using the language of European racists”.

And, by the weekend, amid his dramatic row with the Dutch, Erdoğan himself had reached his peak: “I thought nazism was over,” he thundered, “but I was wrong. In fact, nazism is alive in the west.”

Needless to say, it was not aimed at European officials in Brussels, Berlin or the Hague – but at the Turkish diaspora and domestic audience. The Turkish press accused the Dutch police of behaving like thugs. Geert Wilders, the far-right Freedom party leader in full campaign mode ahead of Wednesday’s Dutch elections, seized the moment, claiming that dual Dutch-Turkish citizens “don’t belong here”. Populists in Europe started feeding off the Turkish rhetoric, and vice-versa.

At present it is hard to see how the vitriol will subside this side of the referendum. But, for Erdoğan, that is a problem for another day.