One of the first tasks facing incoming Croatian President Ivo Josipović will be the question of how, precisely, to deal with his neighbour to the East. Relations between Croatia and Serbia have reached worrying lows over the last month, as a series of diplomatic spats threaten to derail any prospect of regional cooperation.

At the start of January Josipović’s predecessor, Stipe Mesić, raised Serbia’s hackles by choosing Kosovo as the location of his final official visit. Croatia’s recognition of Kosovo’s independence has been a significant source of tension for Serbia, and an official visit—during which Mesić received honorary citizenship and the “Golden Medal of Freedom”—did little to soothe that.

Nor too did the decision by Mesić in the same week to reduce the sentence of Siniša Rimac, a war criminal who was convicted for the 1991 execution of Serb civilians in western Slavonia. Though Mesić on the same day also reduced the sentence of a Serb convicted of the torture of Croat soldiers in Bosnia, the Serbian media has thus far, inevitably, chosen to focus on the pardoning of the Croat.

Mesić provoked yet further ire the following week when he threatened to use the Croatian army in Bosnia if speculation about a Bosnian Serb referendum on independence came to fruition. “If [Republika Srpska Prime Minister] Milorad Dodik scheduled a referendum… I would send the army,” Mesić said; Dodik and Serbian President Boris Tadić were predictably, and understandably, outraged.

Some have argued that Mesić is somewhat of a lame duck, not to be taken seriously: after all, he was constitutionally term-limited and so prevented from standing for re-election, and at the age of 75 he will almost certainly see the presidency as the finale of his five-decade political career. It was inevitable, then, that he would see out the interim by making both official visits and some statements he might otherwise have kept to himself. But until Josipović’s inauguration, he still remains in ultimate control of Croatia and her not-insignificant military; such recklessness will always threaten local stability in a region as temperamental as the Balkans.

Mesić, of course, has not worked single-handedly to undermine Serbo-Croatian relations. In response to Mesić’s threats to send the Croatian army into Bosnia, an angry Tadić accused Mesić of being a “warmonger” and threatened to report Croatia to the UN Security Council; by rising to the bait, Tadić ensured that an ill-considered remark was elevated to the status of a diplomatic incident, and that Serbo-Croatian relations were damaged further.

Tadić later announced that he has turned down an invitation to Josipović’s inauguration ceremony, a major—and staggeringly puerile—diplomatic snub. Tadić claimed that his motivation was the presence at the ceremony of Kosovan President Fatmir Sejdiu, but his recent spat with Mesić must surely have played a part.

Josipović, to his credit, met the snub with aplomb, and has announced that he does not see Tadić’s decision as an act of hostility towards Croatia. Beyond this ventured gesture of polite rhetoric, though, he must surely wonder whether this earliest of interactions is a harbinger of struggles to come.

The issue that bubbles insidiously underneath all of this petty squabbling is, in fairness, far from trivial. In 1999, Croatia filed suit with the International Court of Justice in the Hague, suing Serbia for what it alleges was genocide committed during the Croatian War of Independence in 1991–95.

The case has always been a sore point for Serbia, who look upon the devastation unleashed by Croatia upon the Croatian Serbs in 1995 as a greater crime than any they may have committed in the defence of the short-lived, breakaway Serb state in Croatia. Serbia has spent the last decade trying to force Croatia to drop the case, but in January of this year they instead filed a counter-suit at the ICJ which sought recompense for alleged Croatian war crimes during the same period.

In truth, both sides are almost certainly guilty of some or most of the crimes they try to foist solely upon the other. The court cases—in some hopeful fantasy—might then bring some closure to the events of 1991–95, might bring an end to the denial that plagues the two countries; the prospects are bleak, though. Similar rulings on the Bosnian genocide have done little to foster concord there, and there is nothing to suggest that the judicial evaluation of the Croatian war will be any different.

Until the proceedings at the ICJ are resolved, then, they will continue to act as a wedge driving Croatia and Serbia apart, and will perhaps do so even after their legal completion. When he takes office, Josipović’s foremost foreign policy challenge will be to guide Croatia towards a future in the European Union: that future, though, depends on his salving the wounds of the 1990s. As Croatia’s first president not to have been directly involved in the war, perhaps he will finally be capable of treading this most delicate of tightropes; for the sake of the whole region’s future, he must be successful.