In announcing the role of the F.S.B., or Federal Security Service, in the poisoning, American intelligence officials were confirming the reports of many news organizations, some of which traced the individual agents who tracked Mr. Navalny and attacked him with Novichok, a nerve agent that Russia has used against other dissidents. It was unclear if the United States planned to release a formal report, as it did last week when it confirmed two-year-old findings on the role of the Saudi crown prince in the killing of the journalist Jamal Khashoggi, or would simply summarize the key finding in the Navalny case.
The sanctions are notable chiefly because they are the first Mr. Biden has taken in the six weeks since he became president. While most presidents have come into office declaring they would seek a reset of relations with Russia, Mr. Biden has done the opposite. He has warned that Mr. Putin is driving his country into an era of authoritarianism and promised to push back on human rights violations and efforts to destabilize Europe.
One official told reporters on Tuesday morning that the Biden administration was not seeking to reset relations or escalate confrontations. The test may come in the next few weeks, when the administration is expected to announce its response to the SolarWinds cyberattack, in which suspected Russian hackers bore deeply into nine government agencies and more than 100 companies, stealing data and planting “back doors” into their computer networks.
While the Navalny case was a vivid example of Russian brutality — his F.S.B. attackers stalked him as he traveled across Europe and apparently applied the nerve agent to his underwear — the Biden administration sees SolarWinds as a more direct attack on the United States. Jake Sullivan, the national security adviser, said the response “will not simply be sanctions” and hinted at some kind of covert response as well.
But in the Navalny case, only sanctions were announced — and they might have little effect. History suggests that sanctions work better, if at all, on smaller, less powerful nations, and then only over time. They are often used to signal disapproval without much expectation of changed behavior.