The details of how and why a Russian jet was shot down near the Turkish-Syrian border remain unclear, but one thing can already be said: Russian President Vladimir Putin has misjudged his Turkish counterpart and former friend, Recep Tayyip Erdogan.

According to Turkey's military, one of its F-16s fired on a jet over Turkish territory, after the plane's pilots ignored 10 warnings to leave. So NATO's second-largest military is claiming to have shot down an aircraft in anger that was probably Russian, and is now "consulting" with its NATO allies.

Russia's defense ministry confirmed one of its jets had crashed, but said the plane was flying in Syrian airspace at an altitude of 6,000 meters when it was fired upon from the ground. Putin blamed "backstabbing" and said his country's plane was 1 km inside Syria when hit. So there's a dispute.