IN A SPEECH to the National Democratic Institute last month, Secretary of State Hillary Rodham Clinton talked frankly about the challenges of balancing U.S. support for democracy and human rights with the “complex interests” of a superpower: “We’ll always have to walk and chew gum at the same time,” she said. Ms. Clinton has sometimes tripped while trying to pull that off — as when she appeared to dismiss human rights concerns about China, or when she assured the world on Jan. 25 that the Egyptian government of Hosni Mubarak was “stable.”

This week, however, Ms. Clinton chose just the right moment to prioritize support for human rights over a “strategic” relationship. One day after Russia’s parliamentary elections, which featured both massive rigging and a startling rebuff to Vladimir Putin’s United Russia party, Ms. Clinton strongly sided with the democratic cause. Citing preliminary reports by international observers about ballot-box stuffing and other abuses, Ms. Clinton called for “a full investigation of all credible reports of electoral fraud and ma­nipu­la­tion.” She concluded: “The Russian people, like people everywhere, deserve the right to have their voices heard and their votes counted.”

The unvarnished remarks infuriated Mr. Putin, who finds himself suddenly facing the most serious domestic opposition since he rose to power over a decade ago. As we predicted he would, the Kremlin strongman played a nationalist card, trying to portray Ms. Clinton’s remarks as part of a Western plot against Russia.

Ms. Clinton “set the tone for some activists in our country and gave them a signal,” Mr. Putin claimed Thursday. “They heard this signal and started active work with the support of the U.S. Department of State.”

The Putin regime has been trying to play on anti-American sentiment since before the election; now it is doubling down. At least until March, when he expects to be elected to the presidency, Mr. Putin will likely retreat from, if not dismantle, the “reset” in U.S.-Russian relations that President Obama regards as one of his principal foreign policy achievements.

The administration could respond by ignoring or dodging the Kremlin’s provocations. But to her credit, Ms. Clinton pushed back on Thursday. Asked to respond to Mr. Putin’s remarks, she said that “we value our relationship with Russia” but also “have a strong commitment to democracy and human rights. It’s part of who we are. It’s our values. And we expressed concerns that we thought were well-founded about the elections.”

Ms. Clinton’s outspokenness was particularly important because the popular backlash against Mr. Putin is not over yet. Thousands took to the the streets Monday night to protest the election fraud, and tens of thousands committed on Facebook to attend a rally in Moscow on Saturday. Though Mr. Putin does not yet look like another of 2011’s crumbling dictators, he faces an unprecedented challenge — and a fateful choice between liberalizing his regime or increasing repression. The Obama administration should go on pushing him to choose the path of democratization, however unlikely that is; more important, it should keep telling the majority of Russians who just voted against the regime that the United States is on their side.