SAN FRANCISCO >>President Donald Trump has been on a tear about Google that traces back to a series of unfounded claims about the technology giant circulating among conservatives. Among those claims: that Google interferes with U.S. elections, is biased against conservatives and prefers working with the Chinese military over the Pentagon.

In several tweets issued this August, Trump assailed Google for alleged electoral interference and again brought up claims of its alleged secret involvement with the Chinese government. On Monday, the president reiterated a baseless claim that Google had “manipulated ” the 2016 election in favor of Hillary Clinton, which his campaign’s Twitter feed also picked up .

All of these claims emerged from reports and commentary from conservative pundits and Trump supporters, none backed by convincing evidence. Google has also denied them.

“Distorting results for political purposes would harm our business and go against our mission of providing helpful content to all of our users,” Google spokeswoman Julie Tarallo said.

Here’s where these claims emerged and what’s known about them.

ELECTION INTERFERENCE

On Aug. 6, Trump implicitly suggested that Google had favored Clinton’s 2016 campaign over his and that the company planned to “illegally subvert” the 2020 election as well. On Monday he made the first part explicit, referencing an unspecified study that, he claimed, showed that “Google manipulated from 2.6 million to 16 million votes for Hillary Clinton in 2016 Election.”

Trump won the presidency with an Electoral College majority but lost the popular tally to Clinton by almost 2.9 million votes. Trump has falsely insisted for years that he actually won the popular vote.

The president’s campaign Twitter feed suggested Monday that Trump referenced a 2017 study by psychologist Robert Epstein that found Google showed more pro-Clinton results to undecided voters than pro-Trump results. Google and others have questioned the methodology of the study, which was not peer reviewed by other researchers.

In its final paragraph, the four-page study extrapolated experimental findings from a small group of 21 undecided voters to the electorate as a whole using mathematical models Epstein reported in an earlier paper. Reached by phone, Epstein said his results only showed that search results were biased toward Clinton, not that Google was doing so intentionally to sway elections.

Epstein also noted that those extrapolated findings suggested a pro-Clinton vote shift of 2.6 million to 10 million votes, not the 16 million cited by Trump.

Even that may be too much of a stretch, said Ramesh Srinivasan, an information-studies professor at UCLA, who noted that the study’s finding of alleged search-result bias doesn’t account for other possible influences on voters. “We can’t jump to conclusions that it gave any a candidate millions of votes,” he said.

Like other researchers, Epstein and Srinavasan emphasize that they remain concerned about the opacity of tech platforms like Google and Facebook and their unbridled power to influence elections.

CONSERVATIVE BIAS

In his early August tweets, Trump singled out former Google engineer Kevin Cernekee, who claims Google fired him for posting Republican viewpoints on internal message boards. Google said Cernekee was fired for downloading confidential company documents onto a personal device.

Cernekee apparently drew Trump’s attention after he told Fox News host Tucker Carlson on Aug. 2 that Google executives “really want Trump to lose in 2020. That’s their agenda.” Cernekee offered no evidence for his claim.

“The statements made by this disgruntled former employee are absolutely false,” Google’s Tarallo said.

Cernekee’s situation reflects a larger belief among conservatives that major platforms such as Google and Facebook are biased against conservative viewpoints, both internally and on their public services. Republican legislators have convened several hearings on the subject.

But experts say there’s little evidence to support such claims, which the companies themselves have long denied.

“Trump wants to remind (big tech) that he is watching them,” said Frank Pasquale, a law professor at the University of Maryland and an expert on algorithms and society. He pointed out that some also claim that Google-owned YouTube funnels viewers to far-right videos and conspiracy theories.

All these allegations, Pasquale said, “assume that neutrality or objectivity means having half negative and half positive results.” But if more negative pages about a person or topic exist on the web, he said, a search result will likely produce more negative results.

Cernekee’s personal situation may also be more complex than it first appeared. On Aug. 5, the conservative publication The Daily Caller published posts Cernekee made on Google message boards in which he called for a fund to help white nationalist Richard Spencer after he was punched by a protester.

Cernekee told The Associated Press in a statement that he has “always supported free speech and opposed white nationalism,” and that he spoke in opposition to other employees who supported Spencer getting punched.

GOOGLE AND CHINA

Trump also indirectly referred on Aug. 6 to another unfounded claim gaining currency among conservatives, which is that Google is spurning the U.S. military and instead working with the Chinese. In mid-July, he tweeted about unsupported claims to that effect by technology investor Peter Thiel, a Trump supporter who is also a board member of Google rival Facebook.

In an appearance on Fox News, Thiel offered no proof for claims that Google is working with the Chinese government on artificial intelligence projects and has “likely” been infiltrated by Chinese agents.

Google left China in 2010, and confirmed this summer in a congressional hearing that it shut down an experimental program to relaunch a censored version of its search service in the country. Under pressure from its employees, it has also withdrawn from at least one Pentagon contract.

Google said it has not been infiltrated, and executive Karan Bhatia denied Thiel’s claims in a congressional hearing last month, saying “We take extremely seriously the threat of any penetration of our systems.”

Google does have an AI office in China, which it positioned as a way to employ Chinese engineers who specialize in AI research. Thiel wrote in a New York Times opinion piece that Google’s close AI ties in China are bad for the U.S.

Google said it still works with the Defense Department on other projects, including cybersecurity. And it denies working with the Chinese military.

Others in Trump’s administration have said Google’s work in China isn’t problematic. “I think they’re working for our military, for America, not for China,” Larry Kudlow, director of the National Economic Council, said on Fox News last month.