Facebook’s Oversight Board on Wednesday upheld the social network’s temporary suspension of Donald Trump but declined to decide when, or whether, that ban should be lifted. The decision dashed the former president’s hopes for a swift reinstatement... But it also sent a message that the scope of the board’s power is limited and that the ultimate responsibility for these questions still lies with Mark Zuckerberg and company.

... The board was also careful to note that Mr. Trump’s indefinite suspension has no basis in Facebook’s stated policies. “In applying a vague, standardless penalty and then referring this case to the board to resolve, Facebook seeks to avoid its responsibilities. The board declines Facebook’s request and insists that Facebook apply and justify a defined penalty.”

... It is also, in a sense, a setback for Facebook: Declining to permanently rule on Mr. Trump’s fate on the platform sends the ball back to Mr. Zuckerberg’s court. That’s exactly where he seemed not to want it.

As the decision ricochets across the political world, there will be ample debate as to whether the board made the right call. Upholding Mr. Trump’s suspension sets a precedent for applying the same rules to world leaders as Facebook does to ordinary users, at least in cases of imminent harm — or perhaps even tougher ones, as some communications scholars had suggested. Overturning it, even conditionally, would have militated for a hands-off approach to newsworthy political speech, which seemed to be Mr. Zuckerberg’s own inclination before the winds of power shifted.

... [What] the entire project of the Oversight Board obscures, is that the problems with Mr. Trump’s presence on Facebook — the lies, the propaganda, the incitements — are not just Trump problems. They’re Facebook problems (and to be fair, Twitter problems).

... What Facebook needs to solve its Trump problem is not a binding decision from an appeals court but aggressive investigation into how it shapes the flow of political information. That must include insight into both the workings of its algorithms and moderation processes. It may be just one company, but its unilateral power over the public square became untenable long ago. The long-term solution must involve either stronger checks on its power or reducing its scale.