The Indian Supreme Court will have the final say.

A day after India and Italy put out contradictory statements on the decision reached by a United Nations tribunal in the Italian Marines bail case, the international court on Tuesday clarified matters by making its order public. The Permanent Court of Arbitration ruled that the governments of India and Italy will work to convince the Indian Supreme Court that Salvatore Girone, accused of murdering a fisherman off the coast of Kerala, should be permitted to return to Italy on bail.

Crucially, the court said that Girone's bail conditions are up to the Indian Supreme Court to set, and that the marine will continue to remain under the apex court's authority even while he is in Italy. Equally important was the court's unequivocal insistence that Italy will have to return Girone to New Delhi if it finally concludes that the murder case will be tried in India. Failing to do so would be tantamount to breaking international law.

"Italy and India shall cooperate, including in proceedings before the Supreme Court of India, to achieve a relaxation of the bail conditions of Sergeant Girone so as to give effect to the concept of considerations of humanity, so that Sergeant Girone, while remaining under the authority of the Supreme Court of India, may return to Italy during the present Annex VII arbitration."    

— Permanent Court of Arbitration.

Girone is one of two Italian marines accused of killing two Indian fisherman off the coast of Kerala in 2012, in a case that has soured relations between New Delhi and Rome. Italy is contesting India's jurisdiction over the matter, which took place 20 nautical miles from the Indian coast. The PCA is about to begin arbitration over this matter, looking into whether India has the jurisdiction to try the marines.

Before that part of the case proceeds though, Italy argued that Girone should be allowed to return home to Italy, since the case is not likely to be concluded until 2018. Girone's fellow accused Massimiliano Latorre, was earlier permitted by the Indian Supreme Court to return to Italy for medical treatment.

But concerns have frequently been raised in India about whether Italy would permit the return of the marines under any circumstances, especially after their detention in India turned into an election-time political issue in Italy. The PCA has taken note of this and asked that India must be "assured, unequivocally and with legally binding effect" that Girone will be returned to India if it decides that the case will proceed there.

Even before that, the UN court also clarified that the Supreme Court will have authority over the marine while he is in Italy, and can set conditions regarding his stay there.

"Such arrangements may, inter alia, include the following conditions and guarantees: Italy shall ensure that Sergeant Girone reports to an authority in Italy designated by the Supreme Court of India in intervals to be determined by the Supreme Court of India; Sergeant Girone shall be required by Italy to surrender his passport to the Italian authorities and shall be prohibited from leaving Italy unless the Supreme Court of India grants leave to travel; Italy shall on its own motion apprise the Supreme Court of India of the situation of Sergeant Girone every three months." 

The case remains this complex because it is, in legal terms, sui generis: Unique in such a manner that there are no easy precedents to fall back on. Since India and Italy have both submitted to the jurisdiction of the UN court, its decision in the matter will be hugely important. But none of that can stop India and Italy from sniping at each other, while the cases remain inextricably wound up with domestic politics in both countries.