Dorsey, Facebook CEO Mark Zuckerberg and Google CEO Sundar Pichai will virtually testify before the Senate Commerce Committee on Wednesday regarding potential changes to the provision. Section 230 refers to a portion of the Communications Decency Act of 1996 that protects social media firms from liability for third-party posts on their platforms.

“Eroding the foundation of Section 230 could collapse how we communicate on the Internet, leaving only a small number of giant and well-funded technology companies,” Dorsey said in written testimony obtained by Reuters ahead of the hearing. “We should also be mindful that undermining Section 230 will result in far more removal of online speech and impose severe limitations on our collective ability to address harmful content and protect people online.”

President Trump and leading Republican lawmakers have called for the provision to be changed or repealed amid allegations that social media platforms like Twitter and Facebook have engaged in censorship. Facebook, Twitter and Google have denied allegations that their content moderation practices are biased against conservative viewpoints.

Republican lawmakers have criticized Facebook and Twitter in recent days over their handling of a New York Post report on emails obtained from a laptop that purportedly belongs to Hunter Biden, the son of Democratic presidential nominee Joe Biden. Both Facebook and Twitter took steps to limit the spread of the report, prompting allegations that the social media platforms were engaging in censorship.

In his testimony, Zuckerberg will say that “without Section 230, platforms could face liability for doing even basic moderation, such as removing hate speech and harassment that impacts the safety and security of their communities.”

Pichai will tell lawmakers that Google does not engage in political bias and argue that Section 230 is essential to its business practices.

The Senate Commerce Committee hearing is entitled “Does Section 230's Sweeping Immunity Enable Big Tech Bad Behavior?” The hearing begins at 10 a.m. ET.