Russian air-defense troops just shot down one of the most sophisticated warplanes involved in Russia’s wider war in Ukraine. One problem. It was a Russian warplane. A brand-new Sukhoi Su-34M fighter-bomber. Russian propagandist Yevgeny Poddubny apparently captured on video the Sunday shoot-down over the city of Alchevsk in Russian-occupied eastern Ukraine. “Last night, the air-defense crew of the allied forces destroyed a target in the sky over Alchevsk,” Poddubny wrote Monday. “The nature of the target is not clear. The burning ball fell to the ground for more than a minute.” A video of the wreckage confirmed the plane’s identity:...