Some experts, however, say they may be insufficient. James G. Stavridis, the former supreme allied commander of NATO, wrote in Foreign Policy last week that the first step could be making America’s evidence against Russia public.

“Revealing the names of the officials who authorized the cyberattacks against the United States would put Moscow in an extremely uncomfortable position,” wrote Mr. Stavridis, a former admiral who is now dean of the Fletcher School of Law and Diplomacy at Tufts University. “Ideally, the United States could reveal emails or conversations between Russian officials that demonstrated their intent to undermine the U.S. electoral process.”

But that would run counter to Mr. Biden’s “hope not” statement. Mr. Stavridis and others have advocated other steps, including knocking holes in the Kremlin’s wall of censorship so that opponents of Putin could begin to conspire with one another.

“As a response to the Russian attacks on the U.S. democratic system, this would be both proportional and distinctive,” Mr. Stavridis wrote. It might also be deniable — a key to any covert action approved by the president.

Many others have advocated using cybertechniques to expose Mr. Putin’s links to Russia’s oligarchs and reveal his financial holdings overseas, which are believed to be vast. But such steps would risk escalation, and advisers have warned Mr. Obama that the United States is more vulnerable than most nations.

Mr. Putin initially denied any Russian involvement in the attacks. But in an interview several days ago, he said the important thing was not how emails from Hillary Clinton’s campaign had been hacked, but what they said. Sergey V. Lavrov, the Russian foreign minister, went further. “We did not deny this,” he said of the hacking. But he added that the United States had offered no proof.

A crucial question being debated in the White House is whether warnings like Mr. Biden’s will be enough to make Russia, or others, pull back in their hacking. The calculus behind the decision to formally accuse Russia was that the mere publication of the conclusion could temper the activity.