The annual ritual that is the Victory Day Parade in Moscow serves a dual purpose. It reminds Russia’s citizenry and the Kremlin’s audience across the former Soviet Union of the glorious past. The muscle flexing on May 9 each year benchmarks Russia’s geopolitical fortunes.Last year on the 80th anniversary of the Soviet triumph over Nazi Germany, Russian President Vladimir Putin was flanked by foreign dignitaries from far and wide: Chinese President Xi Jinping, Brazilian President Luiz Inacio Lula da Silva, Slovak Prime Minister Robert Fico, Serbia’s Aleksandar Vucic, Nicolas Maduro of Venezuela, Abdel Fattah el-Sisi of Egypt and Mahmoud Abbas,...