Facebook’s oversight board puts the power back in the platform’s hands to decide Trump’s fate. History tells us that’s dangerous.

The Facebook Oversight Board just announced its decision to uphold the suspension of former President Donald Trump in response to his actions on January 6. But the board ruled that Facebook should not have imposed “the indeterminate and standardless penalty of indefinite suspension” and the platform now must “decide the appropriate penalty” for the former president within the next six months.

With this decision, the board has recognized the harm that Trump caused by using the platform to promote misinformation and harmful rhetoric, but has also chosen to put Trump’s...