A neighborhood in eastern Aleppo after it was retaken by forces backing Syrian President Bashar al-Assad, Dec. 14, 2016 (Kyodo photo via AP).

The harrowing image last month of a Turkish police officer standing over the Russian ambassador he just shot, while blaming Moscow for the devastation in Syria, captures a key foreign policy challenge for U.S. President-elect Donald Trump: How can he attempt to stabilize the Middle East by bringing conflicts to a close, rather than letting Russia and Iran lead the region into further cycles of repression and violence under the rubric of fighting terrorism? Trump’s current defense priority—“to crush and destroy” the so-called Islamic State—plays right into Russian and Iranian machinations, with their selective definitions of terrorism and scorched-earth tactics. […]

Iraqi security forces arrest a suspected fighter with the Islamic State, Mosul, Iraq, Jan. 4, 2017 (AP photo by Khalid Mohammed).

The battlefield defeat of the self-styled Islamic State in eastern Syria and western Iraq is far from certain but increasingly likely. Iraqi government forces, in conjunction with Shiite and Kurdish militias, are slowly liberating Mosul, the largest city the Islamic State has conquered. While the Syrian government is less concerned with the group than with other rebel forces it faces, a Kurdish-Arab militia alliance called the Syrian Democratic Forces is pushing toward Raqqa, the Islamic State’s most important stronghold after Mosul. In parallel, a global coalition led by the United States is undercutting the group’s economic base. The extremists still […]