For years, Moscow insiders have reacted to former Deputy Prime Minister Boris Nemtsov's philippics against President Vladimir Putin with a roll of the eyes. Everyone knew what Nemtsov was going to say. The man Boris Yeltsin almost picked as his successor had become irrelevant, marginalized.

Now Nemtsov's criticism of Putin's Russia has been validated in the most terrible way. On Friday, the opposition politician was killed a few hundred yards from the Kremlin, shot at least four times as he crossed a bridge over the Moskva River.

Just a few hours before his death, Nemtsov went on Ekho Mosky radio to call on Muscovites to join an opposition march Sunday. Another of the event's organizers, anti-corruption activist Alexei Navalny, was pre-emptively sentenced to 15 days in jail, so he will miss the demonstration. So now will Nemtsov, who was as relentless a Putin critic as Navalny, but less popular because of his history as a successful politician in the 1990s.