NIZHNY NOVGOROD, Russia — Shortly before parliamentary elections in December, foremen fanned out across the sprawling GAZ vehicle factory here, pulling aside assembly-line workers and giving them an order: vote for President Vladimir V. Putin’s party or else. They were instructed to phone in after they left their polling places. Names would be tallied, defiance punished.

The city’s children, too, were pressed into service. At schools, teachers gave them pamphlets promoting “Putin’s Plan” and told them to lobby their parents. Some were threatened with bad grades if they failed to attend “Children’s Referendums” at polling places, a ploy to ensure that their parents would show up and vote for the ruling party.

Around the same time, volunteers for an opposition party here, the Union of Right Forces, received hundreds of calls at all hours, warning them to stop working for their candidates. Otherwise, you will be hurt, the callers said, along with the rest of your family.

Over the past eight years, in the name of reviving Russia after the tumult of the 1990s, Mr. Putin has waged an unforgiving campaign to clamp down on democracy and extend control over the government and large swaths of the economy. He has suppressed the independent news media, nationalized important industries, smothered the political opposition and readily deployed the security services to carry out the Kremlin’s wishes.