Academics found that the strength and size of a feminist coalition, as well as its ability to mobilise support and leverage expertise, was a decisive factor in overcoming political and societal opposition and ensuring the adoption of the Council of Europe’s Istanbul Convention.

The convention, which has been in force since 2014, has been ratified by 37 member states of the Council of Europe but eight have chosen not to do so and the treaty has become a particular point of contention in some central and eastern European nations.

In a new study, Dr Anna Gwiazda, from King’s College London, and Dr Liana Minkova, from the University of Cambridge, examined the passage of the treaty in Poland – where it was ratified – and in Bulgaria – where adoption of the treaty was rejected - to see what factors affected its progress.

The convention is a human rights treaty that specifically targets different forms of gender-based violence. Its provisions encompass not only criminal justice responses but also awareness raising and the provision of social support measures to victims such as shelters, medical services, counselling, and legal aid.

As part of the study, the academics examined submissions made to parliament and public consultations, legal opinions and the decisions of courts in Bulgaria along with records of parliamentary bills and debates, votes, and press releases from Poland.

They found networks of advocates opposed to the convention in Bulgaria were both larger and better able to make use of primary resources than the networks of feminist advocates, who supported the legislation. The anti-convention networks were also larger and therefore better able to mobilise popular support, capture public opinion and exert more influence.

In Poland, however, the feminist advocate networks were much larger than those opposed to the convention and had access to more primary resources, had legal authority and utilised wide networks of societal actors in the shape of campaign groups, politicians and NGOs.

The researchers said: “We found that the strength of a coalition – in terms of its size and access to resources – matters.

“In Bulgaria, a constitutional court majority shared the beliefs of the anti-gender coalition. Their formal legal power to declare the constitutionality of international conventions became the primary resource, which blocked ratification.

“While both advocacy coalitions relied on secondary resources, such as signing petitions, participating in public discussions, and providing information, to influence parliamentary debate, and subsequently proceedings at the court, the anti-gender coalition in Bulgaria was larger in size and more vocal, and claimed a larger share of public opinion.

“In Poland, the feminist coalition was strong; it had a partisan majority in parliament, the support of the president, and access to formal power to approve the ratification bill. By contrast, the anti-gender advocacy coalition was weak because it was small in size and lacked primary resources.”

The paper, Gendered advocacy coalitions and the Istanbul Convention: a comparative analysis of Bulgaria and Poland, was published in the International Feminist Journal of Politics.