Tragic turning point

At the time of writing it still isn't 100-percent clear who is responsible for destroying the Malaysian passenger jet MH17 over the separatist-controlled region in eastern Ukraine. We urgently need an independent, international investigation to do find that out.

But all the indications so far suggest that separatists supported by Russia shot down the plane. Not only have separatists been responsible for all the planes shot down in the combat zone so far, they also admitted that for a few days now they have possessed the Buk air defense system necessary to hit a plane flying at an altitude of 10,000 meters (33,000 feet).

Even more revealing, Igor Strelkov, separatist leader and ex-officer in the Russian secret service, boasted on social media shortly after the MH17 crash that his militia had shot down another Ukrainian Antonov AN-26 military plane. But there is no evidence of such an incident, which leads one to suspect that the separatists mistook Malaysian Airlines' Boeing 777 for the Ukrainian military aircraft.

Incriminating evidence

That theory is backed up by intercepted radio messages allegedly exchanged by separatists and officers of the Russian military intelligence agency the GRU, in which a separatist unit in an eastern Ukrainian town a few kilometers from the crash site reported firing a rocket at a plane.

Only an independent, international investigation can bring final clarity on the incident. The analysis of satellite data might be key to working out where exactly the rocket was fired from.

The destruction MH17 massively changes the balance of the conflict that has been raging in eastern Ukraine for weeks. Shooting down a neutral passenger plane that was flying at 10,000 meters with a complex weapon system makes clear that the separatists are not a people's militia that arose out of the political situation, taking to the streets with rifles to fight for justice. Using such systems requires professional training, and though it is certainly difficult to prove that the Russian army and security forces are supporting the militia, it seems likely.

That makes it all the more clear that the conflict in the Donbas region of eastern Ukrainian is not a purely domestic fight, but a proxy war being fought by Ukraine and forces supported by Russia.

Europe must make its position clear

This horrific act of war that has killed hundreds of civilian victims will make it even harder for the West, and especially the European Union, to see themselves as mediators and find a diplomatic solution together with Russia. The calls to intervene more forcefully will grow louder, and to provide Ukraine with direct military support to fight against the separatists. It is also certain that the call for more complete sanctions against Russia will grow even louder, even though the European leaders do not want to be pushed into an escalation of the current confrontation with Russia.

But Western leaders aren't the only ones who have to re-think their strategy. Russian strategy is now also at a crucial juncture: If Moscow does not now clearly withdraw its support for the separatists, the Kremlin has no more opportunity to deny its responsibility for the blood-letting in its neighboring country. Internationally, no one will credit the Kremlin's double game anymore. Russian President Vladimir Putin now has to show whether he really wants peace. Otherwise the idea that Russia's most powerful man has lost control of his army and security forces could gain traction.