Another big change in strategy this year was a willingness to expose adversaries publicly. It is something the Obama administration was also reluctant to do in 2016, when it avoided naming China as the country that stole 22 million files on government employees, or Russia as the source of attacks on the Pentagon, the White House and the State Department.

This year, William R. Evanina, the official put in charge of election security by the Office of the Director of National Intelligence, called out Russia, China and Iran for their efforts to interfere in the elections.

Though criticized by Democrats for not being specific enough, and appearing to equate Iran with much more talented cyberadversaries, Mr. Evanina’s releases put both the public and America’s rivals on notice about what was afoot, including warning that Russia was again trying to assist Mr. Trump.

Mr. Evanina’s announcements in July and August were followed by an announcement in October by John Ratcliffe, the director of national intelligence, that Russian groups had probed state and local networks and that Iran had tried to influence the election by sending spoofed emails as part of a campaign he said was intended to hurt Mr. Trump.

“Naming and shaming the bad actors that are trying to mess with us is a key part of a coherent deterrence strategy,” said Representative Mike Gallagher, the Wisconsin Republican who along with Mr. King led the Cybersecurity Solarium Commission.

Mr. Ratcliffe’s announcement was followed by Cyber Command’s secret operations to interfere with the operations of the Russian group and take down, at least temporarily, the Iranian hacking group tied to Tehran’s Islamic Revolutionary Guards Corps.

American officials said that while Iran opposed Mr. Trump’s re-election, its hackers were hardly playing at Russia’s level. The emails and text messages they tried to send to Americans contained so many spelling, syntax and grammatical errors that they seemed unlikely to fool their targets. Even had they not been taken offline, they posed no threat to turn the result of the elections.