Suppose you were Mark Zuckerberg, ordered by an advisory board to decide how long former President Donald Trump should stay banned from Facebook. How do you make that decision without alienating major constituencies — advertisers, users, employees, shareholders and others — while staying true to your own sense of what Facebook should be? It’s a hypothetical exercise, but one that illustrates the high-wire act Facebook’s leadership now has to pull off. The quasi-independent board said last week that Facebook was justified in suspending Trump over his role inciting deadly violence at the U.S. Capitol on Jan. 6, but ordered the company to clarify its “indefinite” ban.