Google CEO Sundar Pichais appears on a screen as he speaks remotely during a hearing Wednesday before the Senate Commerce Committee. Greg Nash/Pool via AP

WASHINGTON — With next week’s election looming, the CEOs of Twitter, Facebook and Google received a hectoring from Republicans at a Senate hearing Wednesday for alleged anti-conservative bias in the companies’ social media platforms – and were warned of coming restrictions from Congress.

Lawmakers of both parties, citing the companies’ tremendous power to disseminate speech and ideas, are looking to challenge their long-enjoyed bedrock legal protections for online speech.

With worries over election security growing, senators in the Commerce Committee hearing extracted promises from Twitter’s Jack Dorsey, Facebook’s Mark Zuckerberg and Google’s Sundar Pichai that their companies will take needed measures.

Those measures could include blocking meddling by foreign actors or the incitement of violence to overturn the election results.

From left, Twitter CEO Jack Dorsey, Google CEO Sundar Pichai and Facebook CEO Mark Zuckerberg, shown in photos from 2018 to 2020. Jose Luis Magana, LM Otero, Jens Meyer/Associated Press

Facebook, Twitter and Google’s YouTube have scrambled to stem the tide of material that incites violence and spreads lies and baseless conspiracy theories.

Sen. Richard Blumenthal, D-Conn., asked the CEOs if they have a plan “if the president uses your platforms to say, on the day of the election, that there is rigging or fraud, without any basis in evidence, or attempts to say the election is over.”

President Trump has refused to publicly commit to accepting the results if he loses the presidential contest. He also has raised the baseless prospect of mass fraud in the vote-by-mail process.

Testifying via video, the executives said their companies are taking a number of measures, including partnerships with news organizations to get out accurate information. Dorsey said Twitter was working closely with state election officials. “We want to give people using the service as much information as possible,” he said.

Republicans, led by Trump, have accused the social media platforms, without evidence, of deliberately suppressing conservative, religious and anti-abortion views.

During the hearing, Republican senators raised with the executives an array of allegations of bias on the platforms regarding Iran, China, Holocaust denial and other issues.

Democrats focused their criticism mainly on hate speech, misinformation and other content that can incite violence or keep people from voting. They criticized the tech CEOs for failing to police content, blaming the platforms for playing a role in hate crimes and the rise of white nationalism in the U.S.

The Trump administration, seizing on unfounded accusations of bias against conservative views, has asked Congress to strip some of the protections that have generally shielded the tech companies from legal responsibility for what people post on their platforms.

“The time has come for that free pass to end,” Sen. Roger Wicker, R-Miss., the committee’s chairman, said at the start of the hearing. He said the laws governing online speech must be updated because “the openness and freedom of the internet are under attack.”

Wicker cited the move this month by Facebook and Twitter to limit dissemination of an unverified political story from the conservative-leaning New York Post about Democratic presidential nominee Joe Biden. The story, which was not confirmed by other publications, cited unverified emails from Biden’s son Hunter that were reportedly disclosed by Trump allies.

The proposals would make changes to a provision of a 1996 law that has served as the foundation for unfettered speech on the internet. Critics in both parties say that immunity under Section 230 enables the social media companies to abdicate their responsibility to impartially moderate content.

Trump chimed in Wednesday with a tweet exhorting, “Repeal Section 230!”

“It’s amazing. Twitter refuses to allow any mention of the Biden corruption story,” he tweeted. “It’s the biggest story and Big Tech, together with the Lamestream Media, isn’t allowing a word to be said about it.”

Sen. Jon Tester, a Montana Democrat, said, “It’s clear that the directive to hold this hearing comes straight from the White House.”

Zuckerberg acknowledged that Congress “should update the law to make sure it’s working as intended.” Dorsey and Pichai urged caution in making any changes.

The executives rejected accusations of bias. “We approach our work without political bias, full stop,” Pichai said. “To do otherwise would be contrary to both our business interests and our mission.”

The companies have wrestled with how strongly they should intervene with speech. They have often gone out of their way not to appear biased against conservative views – a posture that some say effectively tilts them toward those viewpoints. The effort has been especially strained for Facebook, which was caught off guard in 2016, when it was used as a conduit by Russian agents to spread misinformation benefiting Trump’s presidential campaign.

Wednesday’s session lacked the in-person drama of star-witness proceedings before the coronavirus. The hearing room was nearly empty except for Wicker and a few colleagues, but their questioning was sharp as tempers flared among members.

“Twitter’s conduct has by far been the most egregious,” Sen. Ted Cruz, R-Texas, told Dorsey. Cruz cited Twitter’s limitations on the newspaper story as part of “a pattern of censorship and silencing Americans with whom Twitter disagrees.”

Sen. Brian Schatz, D-Hawaii, went after Republicans, saying the hearing was a “sham.”

“This is bullying,” Schatz told the CEOs. “Do not let U.S. senators bully you into carrying the water” for politicians seeking to discredit their opponents. With their questions, Schatz said, the Republicans “are trying to bully the heads of private companies into making a hit job” on political leaders.

Trump earlier this year signed an executive order challenging the protections from lawsuits under the 1996 telecommunications law.

Ajit Pai, chairman of the Federal Communications Commission, an independent agency, recently announced plans to reexamine the legal protections – an about-face from the agency’s previous position.

In their efforts to police misinformation about the election, Twitter and Facebook have imposed a misinformation label on some content from the president, who has about 80 million followers.

Starting Tuesday, Facebook isn’t accepting any new political advertising. Previously booked political ads will be able to run until the polls close Nov. 3, when all political advertising will temporarily be banned. Google, which owns YouTube, also is halting political ads after the polls close. Twitter banned all political ads last year.