On 8 May 2017, the National Assembly of Slovenia passed a law that deals with the construction of the second railway track from Koper to Divača, in particular regarding the financial plans for the project.

Among the concerns of the opponents were the alleged lack of transparency regarding the finances, questions regarding the proposed track route, and the involvement of Hungary as a potential partner in the construction project.

[5] Supporters of the law cited the already approved financial contribution of the EU, new job creation, the fact that the rejection of the law would result in the beginning of construction being delayed for several years, and the fact that the proposed route is optimal, based on a series of expert studies and agreed upon by all Slovenian cabinets since 2004.

[7] 14,201 voters (0.83%) took part in early vote, which was a considerably smaller number than in the previous referendum on same-sex marriage that took place in 2015.

He also stressed that this project will not turn into "another Teš 6",[9] referring to the construction of a new power plant in Šoštanj which was marred by a series of corruption affairs.

[9] Following the results of the referendum, the impact litigation activist Vili Kovačič contested the results in the Supreme Court, claiming that the law regulating referendums and civil initiatives were not compatible with the constitution, citing the fact that the government had used €97,000 of public funds on the campaign in support of the proposed law.

Cerar stated that the court verdict was "one blow too far" by those who wanted to block the development of Slovenia, mentioning tensions in the coalition among reasons for his resignation.