One of the more controversial legal protections internet companies like Facebook and Google receive—not being liable for offensive or illegal content posted by users on their services—faces a growing challenge in Washington, prompting intensifying lobbying on both sides of the issue.

While the privacy of consumer data held by tech companies has garnered a lot of attention in the past year, the debate about whether internet companies should retain liability protection—as written in Section 230 of the Communications Decency Act—is shaping up as an equally far-reaching issue.