Reid Hoffman, the tech billionaire whose money was spent on Russian-style social media deception in a Senate race last year, apologized on Wednesday, saying in a statement that he had not approved the operation and did not support such tactics in American politics.
Mr. Hoffman said he had no idea that political operatives whose work he had financed had used fakery on Facebook and Twitter in the special Senate election a year ago in Alabama. But he had an obligation to track how his money was spent, he said, and he promised to exercise more care in the future.
I categorically disavow the use of misinformation to sway an election, said Mr. Hoffman, a co-founder of LinkedIn and a prominent figure at the intersection of Silicon Valley and Democratic politics. He said he had financed organizations trying to re-establish civic, truth-focused discourse and was embarrassed to learn his money had been spent on disinformation.
The New York Times and The Washington Post reported last week that $100,000 from Mr. Hoffman was spent on a deceptive social media campaign to aid Doug Jones, the Democratic candidate, who barely defeated the Republican, Roy Moore.
The money went to a small group of social media experts that included Jonathon Morgan, the chief executive of New Knowledge, a cybersecurity firm.
They created a Facebook page intended to look like the work of conservative Alabamians, and used it to try to split Republicans and promote a conservative write-in candidate to take votes from Mr. Moore.
They also used thousands of Twitter accounts to make it appear as if automated Russian bot accounts were following and supporting Mr. Moore, according to an internal report on the project. The apparent Russian support for Mr. Moore drew broad news media coverage.
Democratic political strategists say the small Alabama operation which accounts for a minuscule share of the $51 million spent in the contest was carried out as a debate about tactics intensified within the party.
Democrats had been shocked to learn of Russias stealth influence campaign to damage Hillary Clinton and promote Donald J. Trump in the 2016 presidential race. But at least a few Democrats thought their party could not shun such tactics entirely if others were going to continue to use them.
The Alabama operation is among the first examples to come to light of such underhanded methods on social media in American politics. But because such efforts are generally very easy to hide and very difficult to trace, it is possible that other instances have gone undetected.
In 2017, through a fund called Investing in Us, Mr. Hoffman gave money to a small company, American Engagement Technologies. The companys leader, Mikey Dickerson, is a former Google employee who founded the United States Digital Service during the Obama administration to try to upgrade the federal governments use of technology. An associate of Mr. Hoffmans said that his total grant to American Engagement was $750,000, which also went toward other political races and social media research. Mr. Dickerson has declined to comment.
American Engagement then passed $100,000 to Mr. Morgan and other researchers. Mr. Hoffmans statement says the money went to Mr. Morgans company, New Knowledge, but Mr. Morgan said the Alabama project was carried out separately from the company.
The revelations of and fallout from the operation are being closely watched. Some American political experts fear that the Russian influence campaign of 2016 could become a dangerous model for stateside politics, with dirty tricks on social media becoming common. Laws and regulations have not been updated to cope with such a threat.