Russian opposition leader Alexei Navalny’s death in jail on Feb. 16 follows a long list of murders and suspicious deaths of opponents of Russian dictator Vladimir Putin. Since he came to power in 1999, more than 20 Putin critics have been killed or died mysteriously. Many other enemies of the Kremlin have survived assassination attempts. Some of the critics investigated alleged crimes of Russian intelligence services, while others criticized Putin’s wars in Chechnya, Georgia and Ukraine. The methods employed ranged from poisoning and shooting to plane crashes. Another long litany is that of ki…