Mr. Zuckerberg, in particular, has come to see his own role in guiding Facebook’s community, and the trust the community places in him, as crucial to the fate of the corporation. So when the heat from American lawmakers regarding ads placed by Russian trolls on Facebook began to rise, Mr. Zuckerberg had no option to ignore it; he had to say something.

But these messages aren’t just show. Inside Facebook, Mr. Zuckerberg’s exhortations carry the weight of God. That’s why the detailed plan he offered to address election meddling is a very big deal.

Like all tech leaders, Mr. Zuckerberg is often hailed as a visionary, but his primary talent is as a reactor. His true skill is not in seeing ahead, but in looking back and fixing where Facebook has failed. And what’s noteworthy is that when he marshals Facebook’s considerable resources to address a problem, Mr. Zuckerberg has a track record of making things right.

I am not asking you to blindly accept that Facebook will be able to completely address the role it plays in modern propaganda wars. On Russian meddling specifically, it took Facebook more than 10 months after the election to reveal that Russian trolls had bought ads through Facebook, and then it further dragged its feet on deciding to make those ads available to Congress.

What’s more, Mr. Zuckerberg’s initial reaction to the question of Facebook’s role in the election was marked by a reflexive defensiveness.