When the chief executives of Facebook, Google and Twitter testify Wednesday before a Senate committee on how they control content on their services, they will argue against rolling back Section 230 of the Communications Decency Act, which shields internet companies from lawsuits over user-generated posts. That’s where their agreements may end.

Much as with their diverse approaches to handling problematic posts involving everything from hate speech to unfounded political allegations, the CEOs diverge on what Congress should do about Section 230, according to testimony released in advance of the hearing, interviews with lobbyists for tech companies and advocates pushing for an overhaul of the law. The lack of a unified front could weaken the tech companies’ ability to parry both political parties’ attacks, which have intensified in the run-up to this year’s U.S. presidential election.