When Russia launched an air campaign to support Bashar al-Assad, it was banking on a ground force of Syrian troops to finish what its warplanes started. However, more than 12 weeks later, Syria’s army and the large numbers of Shia militias that back it have made few meaningful gains on the ground. Meanwhile, Moscow’s jets have added a new layer of carnage, reportedly killing at least 600 Syrian citizens, including 70 in Idlib on Sunday. In Syria’s north and in opposition-held parts of the cities of Hama and Damascus, the destruction wrought on civilian infrastructure and population centres over the...