Last month has proven to be catastrophic for the credibility of one of Russia’s most touted air defense systems. The troubles for the Pantsir S1 air defense system in Libya began when Khalifa Haftar’s yearlong Tripoli offensive against the Ankara-backed Government of National Accord (GNA) began to collapse. Believed to have been supplied to the Libyan strongman as early as last year by his backers in the Gulf, the Russian system was meant to be used as a trump card against Turkey’s combat unmanned aerial vehicle (UAV) air interdiction operations. Yet, after a major GNA counteroffensive last month, and the...