There is much talk these days about the need for the United States to reengage Russia’s leadership in a strategic dialogue.

But would Russia speak with one voice?

We’re already familiar with this basic problem because it has dogged the Bush administration. Throughout the Bush presidency, foreign policy has been personality-driven and intensely factionalized: ideologues associated with Rumsfeld and Cheney have battled pragmatists aligned with Powell and, to some extent, Gates and Rice. These divisions wreaked havoc on the coherence of U.S. foreign policy, particularly in nonproliferation where policy goals lurched between regime change and behavior change. (I highly recommend Mike Chinoy’s book Meltdown, which offers a riveting account of the Bush administration’s utterly dysfunctional North Korea policy process.)

Could a similar dynamic emerge in Russia? President Medvedev is the official Russian head of state, but it is no secret that Vladimir Putin — who as Prime Minister has virtually no legal control over the levers of government and, at least according to Russia’s 1993 constitution, serves at the pleasure of the president — nevertheless wields outsize influence. Even if the two men are in agreement on most issues, this arrangement undermines formal, transparent lines of authority by replacing them with contingent, potentially opaque personal relationships.

But where there is policy disagreement, the prospects for mischief and policy entrepreneurship by factions are very high. Just as infighting within the Bush administration made it extraordinarily difficult and frustrating for foreign countries to deal with Washington, infighting in Moscow would complicate dealings with Russia.

Medvedev and Putin are believed to be very close, and I am unaware of concrete, credible evidence to the contrary. But the durability of their relationship has not been seriously tested — yet. Like many countries, Russia faces extraordinarily difficult economic times ahead. Probable recession, low energy prices, and a lack of investment capital will impose tremendous demands on the Russian state to protect its citizens and companies, and it is inevitable that some factions will fare better than others due to resource constraints and rampant corruption. These problems could stoke political factionalization, lead to even more corruption, and strain Medvedev and Putin’s informal powersharing arrangement.

Moreover, in January Moscow will see its favorite whipping boy, the Bush administration, replaced by a popular new U.S. administration that has signaled a more multilateral approach to foreign policy. With the unifying foreign nemesis gone, cracks in Moscow’s foreign policy consensus may begin to appear.

None of this is to suggest that the United States shouldn’t seek a new strategic dialogue with Russia. It most emphatically should. But it must go in with open eyes and realistic expectations.