Ostensibly, President Vladimir Putin remains popular in Russia. He has presided over impressive economic growth. So why is he so frightened, so unwilling to allow a few thousand opponents to peaceably assemble in central Moscow? The answer ironically may lie in his success at choking off freedoms in his country. The media have been muzzled, and many local elections have been eliminated; the normal mechanisms for people to express their desires and complaints in a healthy society are gone. As a result, to gauge public sentiment Mr. Putin is left with little but the reports of his old colleagues in the former KGB, and that may encourage a tendency toward paranoia.