Editor's note: Daniel Treisman is a professor of political science at the University of California, Los Angeles, and author of "The Return: Russia's Journey from Gorbachev to Medvedev."
(CNN) -- The unexpectedly harsh 14-year sentence handed down to jailed Russian tycoon Mikhail Khodorkovsky last week may have finally laid to rest one common theory about Russia's politics.
Ever since President Dmitry Medvedev's election in February 2008, rumors have circulated of a secret struggle between him and his longtime mentor, Prime Minister Vladimir Putin, over the country's future.
Medvedev is cast as a liberal, eager to open up Russia's politics, modernize the economy and root out corrupt police officers and judges. Putin, with his salty witticisms and security service friends, is seen as a reactionary defender of the status quo.
The two men's styles certainly differ. Consider how they spent last summer. Medvedev visited Silicon Valley in California to plead for high technology investments, and photographed the visit for his blog. Putin rode a Harley Davidson through southern Ukraine, escorted by leather-clad bikers.
Almost any turn of events can be fitted into this framework. Each reform idea that surfaces is attributed to the "good" Medvedev. When most disappear without trace or prove entirely cosmetic, their failure is chalked up to the "bad" Putin.
Over the last three years, the perceived jockeying between the two men has provided an element of drama. Russia's democrats have repeatedly detected a "Medvedev thaw," only to lose sight of it again as the Putin freeze returned. For many, the tragic farce of the second Khodorkovsky trial will be the last straw.
In fact, the evidence of a split between the two leaders has always consisted of one-third verbal nuance and two-thirds wishful thinking. Frictions naturally arise between the two leaders' staffs. Medvedev and Putin do sometimes differ on tactics. For instance, long-time Moscow Mayor Yury Luzhkov may have been fired in September a little quicker than Putin would have liked. Still, both agreed he had to go.
Such details pale, however, beside the strong ties that unite the two men. Close acquaintances for 20 years, much of it spent working together, they have a trust based on shared experience. They also have the same central interests and goals.
Their priority is hanging onto power, and, as both recognize, that means finding a way to keep the incomes of Russians rising. Medvedev's role in this is to attract foreign investment and gin up the Russian economy with high tech projects. Putin's is to funnel largesse to the masses. To cushion the effects of the global financial crisis, he increased public spending by more than 7% of GDP in 2009, and raised pensions by 37% after inflation in the first 11 months of 2010.
Holding onto power also requires appealing to two distinct constituencies, and here, too, is a division of labor. Medvedev's task is to reach out to the more prosperous, educated elite, based mostly in Moscow and St. Petersburg. Putin's is to bond with Russians in the provinces, who tend to be more nationalistic, suspicious of the West and unsympathetic to billionaires such as Khodorkovsky.
As a result, their messages and rhetoric differ, and sometimes even conflict. Medvedev tweets, Putin growls.
Even were Medvedev tempted to challenge Putin, he would recognize the political harness that constrains him. To pass a law, he needs the support of the parliament, which is dominated by the United Russia Party Putin heads. To implement policies, he relies on the government -- led by Prime Minister Putin. Should he try to fire Putin, the parliament would need to approve a replacement.
The "good cop, bad cop" routine offers considerable flexibility. Were economic conditions to worsen sharply, the two leaders might at some point decide a liberal turn was in their long-run interest. If so, Medvedev might start winning more "battles" over policy.
Were international markets inclined to punish the Kremlin for its treatment of Khodorkovsky, "liberal" Medvedev might be called upon to issue a pardon. But don't hold your breath. Putin evidently learned a different lesson from the surge in Russian stock prices in the years after Khodorkovsky's 2003 arrest.
And so the show continues. Putin, asked about Khodorkovsky in December, announces that: "A thief should sit in jail." Medvedev strikes a legalistic pose, implicitly scolding Putin: "Neither the president, nor any other official, has the right to express his or her position on this case or any other case before the verdict is passed." Words that change nothing. The judge then issues his verdict and the toughest sentence. All have played their parts exactly as written.
The opinions expressed in this commentary are solely those of Daniel Treisman.