THE RETURN of Vladi­mir Putin to the Russian presidency ought to have caused the Obama administration to reshape its policy toward the Kremlin. Putin based his election campaign in large part on anti-Americanism; he has increasingly pursued policies contrary to vital U.S. interests, such as his military support for the Syrian regime of Bashar al-Assad and his threats against NATO’s European missile-defense system.

Most important, Mr. Putin’s decade-old autocratic regime is looking shaky. Hundreds of thousands of Russians have turned out to demonstrate against fraud in the presidential and parliamentary elections, and to demand political reform. Many Russian experts are saying that the Kremlin’s economic and political policies are unsustainable, and that Mr. Putin will not finish his six-year term unless he makes major concessions to the opposition — which he shows little sign of doing.

Remarkably, however, President Obama has responded to Mr. Putin’s return to the presidency by strongly affirming his commitment to partnering with the strongman. His meant-to-be-confidential assurance to outgoing President Dmitry Medvedev on Monday, that “after my election I have more flexibility” to solve “all these issues, but particularly missile defense,” was only the latest sign that Mr. Obama has decided to bet on deal-making with Mr. Putin rather than on democratic change in Russia.

Days after Mr. Putin’s election in a vote that international observers described as not free or fair, the White House issued a statement saying that Mr. Obama had called Mr. Putin “to congratulate him on his recent victory” and propose that “the successful reset in relations should be built upon during the coming years.” The statement made no mention of democracy or human rights in Russia, and Mr. Obama has said nothing on the subject since the election.

Instead, Mr. Obama has invited Mr. Putin to meet in Washington shortly after his inauguration in May to discuss an agenda that Mr. Obama says will include a new agreement on reducing nuclear weapons. His lobbyists are pressing hard, meanwhile, for the repeal of a 1974 law limiting trade with Russia while resisting a congressional proposal, supported by many Democrats, that would tie the repeal to a new law punishing Russian human rights abusers.

Last month Secretary of State Hillary Rodham Clinton said Moscow’s obstruction of action by the U.N. Security Council on Syria was “just despicable.” Yet last week the Obama administration agreed to support what amounts to Russia’s plan for keeping the Assad regime in power, by dispatching a U.N. envoy to broker peace. Mr. Obama’s assurance to Mr. Medvedev, meanwhile, has raised a reasonable question: What “flexibility” will Mr. Obama be prepared to offer on missile defense, given that Mr. Putin surely will not be satisfied with anything short of scrapping the system or giving Russia a veto over its use?

Mr. Obama said Tuesday that “at a time of great challenges around the world, cooperation between the United States and Russia is absolutely critical to world peace and stability.” But that cooperation — and progress on Mr. Obama’s priority of more nuclear arms reductions — should not come at the expense of U.S. defense and security interests. Moreover, Mr. Obama would be foolish to center his policy on an autocrat whose people are clamoring for democratic change. Has nothing been learned from the Arab Spring?