Russian opposition leader Alexey Navalny attends an opposition march in memory of murdered Kremlin critic Boris Nemtsov in central Moscow on February 25, 2018.
Russian opposition leader Alexey Navalny attends an opposition march in memory of murdered Kremlin critic Boris Nemtsov in central Moscow.
  • Alexey Navalny, Putin's most prominent critic, commented on US politics months before his death.
  • Navalny expressed concern over a potential second Trump term in letters to a friend.
  • Trump briefly mentioned Navalny's death in a Truth Social post on Monday.

Alexey Navalny, the dissident and political nemesis of Russian President Vladimir Putin, spent the last few years of his life behind bars but still managed to stay connected to the outside world.