Rumors of war abound. The simmering conflict of the Balkans may well grow to war again.

So go the whispers from Bosnia, Kosovo and Serbia. From Reuters to the The Globe and Mail, reports of war-like rhetoric between Kosovo and Serbia have emerged.

The background

The disputes of the Balkan Wars in the 1990s were never fully put to rest. A Serb Republic in Bosnia still holds about half the country based on the frontlines of 1995. KFOR, the NATO-led Kosovo protection force, still has some 4,600 troops in Kosovo to guarantee peace between Kosovars and Serbs. Much remains unresolved.

The last round gave victories to NATO and the United States. Forcing Serbia out of Kosovo while halting its conquest of Bosnia were huge victories in the heady 1990s.

Russia, long a protector of Balkan Orthodox powers, lost influence. Vladimir Putin remembers that; when attacked over Crimea, his administration retorted that the Black Sea peninsula is to Russia what Kosovo is to the Kosovars.

The Balkans have thus remained a frozen geopolitical frontline between varying powers. It is a contest between the West and Russia; specifically, the West’s values-based diplomacy, which motivated intervention two decades ago, and Russia’s historical interest-based approach to the world.

It also a contest between Christian and Islamic Europe: Christian Serbs face down Bosnian and Kosovar Muslims, with the Serbs backed by Christian Russia and the Bosniaks and Kosovars by Muslim Turkey. This is a clash of an old sort: the mosque versus the church in a contest going back to the Ottoman era. In a place that forgets little, the past matters.

Finally, there is the battle of nations. Bosniaks struggle to put together a nation state out of a frontier. Kosovars hope to advance beyond being mere Albanian migrants on ancestral Serb land. Serbs fear more losses in the future; having lost Montenegro in 2009, Serbia has sunk nearly as low as it can.

Back to the barracks?

Serb power was checked by NATO-led values, when the alliance decided to not stand by and let ethnic cleansing happen in the 1990s.

Still enjoying the backing of Russian military hardware, Serbia’s armed forces are more capable than those of its neighbors. In a war, Belgrade can be confident in victory with anyone around it.

There is now a feeling — in some quarters, a hope — that Donald Trump’s election in America means the death of values-based geopolitics in the West.

If so, there are no core interests of NATO in the Balkans beyond credibility. Should NATO leave Kosovo, it would be a clear signal that Serbia could embark on the warpath again to reclaim lost lands.

This is matched by a fear on the Bosnian and Kosovar side. While Turkey has shown both sides some support, Ankara acts only within the framework of NATO itself. If NATO leaves the Balkans, it means Turkey would have to face down both Serbia and Russia on its own. Already desperately trying to cobble together peace in Syria with the Russians, such a confrontation is not in Turkey’s best interest.

Grand bargain

The real risk is that Trump may give up Kosovo as a bargaining chip with Putin to gain Russian cooperation to fight Sunni supremacism in the Middle East.

It’s been nearly twenty years since there was any major fighting in the Balkans. Most Americans may have little to no memory of the last round. This would give the president cover for ending the KFOR mission.

Yet such a grand bargain may be stillborn. Democrats and Republicans are closing ranks against rapprochement with Russia. Reports of Kremlin hacking and Russian bombing in Syria have outraged nationalists, human rights advocates and career politicians alike.

To know what will happen in the Balkans, one must watch the Russo-American relationship. If Trump gets on better terms with Russia, it may mean war again in Southeast Europe.