Russian President Dmitry Medvedev’s choreographed announcement that he will support Prime Minister Vladimir Putin’s election as president in next year’s elections likely means more of the same in Russia’s domestic conduct and foreign policy. Much-discussed differences between Medvedev and Putin have generally amounted to less than meets the eye and, as a result, a formal transition back to Putin’s leadership will provide continuity in policy. Less clear is the sustainability of the country’s leadership model.

In America, much has been made of Dmitry Medvedev’s calls to strengthen the rule of law, reduce corruption and promote diversification and innovation in Russia’s economy and many have found Medvedev more attractive than Mr. Putin. In reality, however, virtually none of Mr. Medvedev’s rhetoric was new; Putin set out nearly identical objectives for Russia during his presidency. Their respective annual speeches to Russia’s parliament—equivalent to the State of the Union Address—demonstrate that these goals originated with Putin.

Likewise, some have concluded from President Medvedev’s periodic meetings with democracy and human rights activists, and his occasional criticism of Russian government practices, that Medvedev is “more democratic” than Putin. The question few asked, however, was whether Medvedev would have pressed for a free and fair election, or run a clean campaign, if he had sought re-election rather than gamely endorsing Putin. Medvedev himself did nothing to suggest that he would have competed fairly.

In foreign policy, Mr. Putin sought a “reset” of his own with the United States in 2001 by reaching out to the Bush administration after the September 11 attacks. The US-Russian relationship eventually collapsed under the weight of Russia’s disillusionment with the Iraq war and US democracy promotion, on the one hand, and American concerns about Russia’s governance and assertive foreign policy, on the other.

New leaders in both countries gave the United States and Russia a chance to try again in 2009. Since then, Medvedev’s end of the Obama-Medvedev relationship would have been impossible without Putin’s explicit backing for some steps and tacit acceptance of others.

Moscow’s foreign policy since Russia’s independence has ultimately been pragmatic and defensive. During the 1990s, Russia was so weak that its first president, Boris Yeltsin, had little choice. Russia’s subsequent economic growth, mostly a result of high energy prices, has provided Mr. Putin and Mr. Medvedev with the illusion of choice, but little more than that due to the country’s considerable domestic problems and matching investment needs.

Notwithstanding Vladimir Putin’s tendency toward bravado, Russia needs a peaceful and stable international environment—and wealthy foreign partners, whether in the West or elsewhere—to succeed.

With this in mind, a restored President Putin will have his own motives for continuing improvements in US-Russian relations. Whether the US-Russian relationship can stay on track is another matter, however: Putin will meet considerable skepticism in the US Congress, particularly from Congressional Republicans. America’s Republican presidential candidates are also quite likely to describe Putin’s apparent Kremlin homecoming as a failure of the Obama administration’s reset policy. This could diminish the Prime Minister’s enthusiasm for working with Washington once he takes up his new-old responsibilities.

Of course, Russia needs internal stability even more than external stability—and this appears to be the main driver behind Putin’s determination to return to the presidency, Medvedev’s willingness to cooperate, and many Russians’ acceptance of their tag-team approach to leadership.

Revealingly, Putin’s and Medvedev’s attempt to ensure stability by switching jobs demonstrates just how unstable the country is; Mr. Putin cannot leave office securely without fearing for his future, Mr. Medvedev lacks sufficient political clout to rule a troubled nation on his own, and the two of them have prevented the emergence of other potential national leaders who could move the country forward.

First Deputy Prime Minister Alexei Kudrin’s announcement that he will not work for Medvedev illustrates the inevitable disappointment of ambitious second-tier officials in Russia.

Medvedev’s deference to Putin may answer the question that everyone has been asking, but it does not answer the larger questions about Russia’s future. First among these is whether Mr. Putin and Mr. Medvedev will genuinely work to strengthen the rule of law in Russia. Absent that, corruption will persist and investment, innovation, and diversification will remain unlikely—as will democracy.

If Russia’s economy slows, as many expect it will, popular anger with Putin and Medvedev may well grow, presenting the rearranged tandem with potentially unpleasant options. Twenty years after the Soviet Union collapsed, Russia’s leaders appear to face the same dilemmas that lay before former Soviet President Mikhail Gorbachev: how to spur economic growth without giving up political control and how to maintain a stagnant and undemocratic system without resorting to large-scale violence.