In late February, Russian propaganda attempted to instill terror into Ukrainians by claiming that up to 70,000 Chechen fighters were headed to Ukraine to support Russian troops. With a population of about 1.2 million, Chechnya is a Russian republic in Eastern Europe’s volatile North Caucasus region, which saw the rise of jihadist groups in the 1990s. The region’s predominant religion is Islam, which is strictly enforced by government authorities. Chechnya is run by a close ally of Russian President Vladimir Putin, who makes sure it remains firmly in the Kremlin’s orbit. The legend of Chechen warriors stretches back nearly 200...