MOSCOW — If there was ever a moment for a Communist comeback, it would seem to be now.

The Communists were big winners in recent parliamentary elections, capturing nearly 20 percent of the popular vote and cementing their place as the most formidable opposition bloc, as voters began to express their exhaustion with United Russia, the governing party of Prime Minister Vladimir V. Putin.

Meantime, the world financial crisis, which has toppled governments and spawned social unrest in the euro zone, has provided reams of material for railing against the excesses and evils of capitalism — with warnings of “debt bondage,” “fictitious capital” and “financial imperialism.”

But rather than starring in the Great Red Revival, the longtime party leader, Gennadi A. Zyuganov, has instead found himself walking a political high wire.

In recent days, he has sharply criticized the elections as marred by fraud, while simultaneously maneuvering to claim the spoils of victory in those same elections, including some important committee chairmanships in the Duma, the lower house of Parliament.