Violence in Ukraine proves the limits of high-level diplomacy. But the talking must continue, nonetheless

Vladimir Putin, may well be continuing to fund, encourage and possibly arm the separatists in eastern Ukraine

The deal arranged over Ukraine last week is in danger of falling apart with the ink on the paper barely dry. The deaths of five people following a shootout at a barricade near the pro-Russian town of Slovyansk has dealt the fragile Easter truce a terrible setback. Across Ukraine’s restless east, there is no sign of pro-Russian separatists disarming and evacuating government buildings as was intended.

The news is disappointing but not a great surprise. Experience of the numerous peace deals hatched in the 1990s during the wars in former Yugoslavia teaches that agreements reached in far-off cities in Western Europe have a marginal impact on the fighters on the ground. The mistake we make now is the same as the one made then: to imagine that the men in balaclavas on the barricades are just puppets – ready to respond to the slightest tug from distant wire-pullers, whether in Moscow or Kiev.

Unfortunately for diplomacy, many of these men are neither puppets nor mercenaries but pumped-up, impassioned would-be martyrs for their respective causes. That is why America’s latest threat, which is to tighten the sanctions regime on the Kremlin if the Geneva deal is not honoured in full, won’t change much.

The Russian President, Vladimir Putin, may well be continuing to fund, encourage and possibly arm the separatists in eastern Ukraine. But even if Russia disengaged completely, it is a fantasy to imagine that what looks like a gathering revolt against Kiev will just melt away at this stage. Now blood has been shed, defusing tension will be even more difficult.

Even that doesn’t mean Ukraine is doomed and that a horrific war on Europe’s eastern border is inevitable. But what the peacemakers have to take on board – which will be unwelcome because it complicates matters – is that no talks on Ukraine are likely to get far unless they include the rebels, as well as the US, Russian and Ukrainian governments, and the rest.

Of course, involving these rebels in the peace process will be difficult. Outraged partisans of the pro-Western government in Kiev will complain that it smacks of appeasement, that Ukraine is being betrayed and that violence is being rewarded. Facing down that clamour will not be an easy task.

The other difficulty is working out who to talk to. The revolt in eastern Ukraine has spread in a sporadic, ad hoc manner and the only umbrella body that the rebels have formed, the so-called Donetsk People’s Republic, lacks an identifiable leadership. We still don’t know who speaks for the east, and we must be wary of legitimising the loudest voices as the most authentic representatives of the community.

Nor should economic pressure on the Kremlin be relaxed. Even if the Putin regime is not directing events in Ukraine in the fashion that Washington maintains, it is complicit in them. The Russian media’s constant demonisation of the new government in Kiev as a bunch of fascists is outrageous and inflammatory. But holding the Kremlin to account for this and other matters will only get us so far. The alienated Russian-speakers of eastern Ukraine must be persuaded into the discussion. Otherwise, Monday’s incident in Slovyansk will be no exception and the barricades will remain up.