However, compelling evidence emerged at the same time that the Russians were upping the ante in Ukraine. After the fall Slavyansk, until then the epicenter of the rebel’s military, Russian forces apparently launched short-range rocket strikes on Ukrainian positions and the U.S. government stated that the rebels had started to receive more heavy equipment from across the border, including artillery and armored vehicles.

This may well have included the Buk surface-to-air (SAM) missile system that apparently brought down MH17. Although the rebels subsequently claimed not to have any such systems, they incautiously had tweeted a picture of at least one in their arsenal at the end of June. The Buk may have been stolen from Ukrainian government stocks, as they and Moscow claim. Or it may have come directly from Russia. It makes little difference. The fact is that without Russian protection (and perhaps technical assistance), the rebels would not have been in a position to launch the fateful missile.

And that one missile has redefined this six-month-old war.