“I don’t regret anything,” wrote Alexei Navalny to a journalist friend in 2021.

The Russian dissident entertained no illusions about his future when he penned that letter from prison. His darkest imaginings materialized last week when Navalny fell ill, collapsed and died after a meal in the Arctic penal colony where he was imprisoned.

Navalny’s death deprives Russia of its most thoughtful and powerful opposition to President Vladimir Putin and his criminal clique. The dissident has been likened to Nelson Mandela, similarly accepting a life and likely death in prison to the alternative of freedom in exile. His murder — there is no more accurate description — is another indication of the impunity that Putin thinks he enjoys. He must be disabused of that fantasy; Navalny must not have died in vain.