Once seen as steady partners in the post-Soviet space, Russia and Azerbaijan are now caught in a spiralling diplomatic row. A series of events over the past six months, from the crash of an Azerbaijani passenger jet that Baku blames on Moscow to the recent deaths of ethnic Azerbaijanis in Russian police raids, have sharply tested the limits of this relationship. Add to that Azerbaijan’s growing tilt toward Turkey and Ukraine, and the result is a confrontation that threatens to reshape power dynamics in the South Caucasus. The fallout is no longer limited to words.