Among old Russia hands, the smart thing to say about Mikhail D. Prokhorov, the billionaire who is running for president, is that he is a puppet of the Kremlin. He’s not a real opposition politician, the argument goes, he is merely a liberal-sounding insider who has been given Prime Minister Vladimir V. Putin’s blessing to compete to make the race look more legitimate and to split the liberal vote.

All of this is true. But when I interviewed Prokhorov in Moscow a few days ago, I realized that it missed the most important point — what Prokhorov’s candidacy, and the man himself, tells us about the battle raging today inside the Russian governing elite.

When people take to the streets to challenge their regimes, particularly in societies that had been dismissed as apathetic, the most exciting story is the protesters. Many of them are fresh faces, and they can be painted in the idealistic colors of the outsider.

The opposition is certainly important — and it usually also has the virtue of being right. But the fate of the protest movement is very often decided not on the raucous streets where the opposition marches, but in the grim offices where the governing establishment decides how it will respond and how it can hang on to the loot it acquired while in power.

That was the case in the Soviet Union 20 years ago, when three career Communist Party officials gathered in a hunting resort in Belarus to sign the death warrant of the regime that created them. It was true of the Orange Revolution in Ukraine, which was led by a man who had served as prime minister and central bank chief for the president he was defying. And it was decisive last year in Egypt, where Hosni Mubarak lost the support of the military.