And so, it comes to this. After Facebook suffered the worst single day in history on the American stock market, we're at the moment of reckoning for  Mark Zuckerberg.

One day, we will look back. And we will recall that today he decided whether:

A) He was satisfied to go down in history as "only" an iconic entrepreneur--the man who, in his own words, "designed the platform" of Facebook


B) He would become a truly great leader--an iconic American whose ultimate accomplishments might transcend his business success 

If he goes with option A, it's still pretty amazing. He's probably one of the top 100 business leaders in our nation's history. He'll be remembered longer than I will, anyway. 

But option B is the truly transcendental opportunity. From time to time, we've seen indications that he wants to go beyond--but if so, now is the moment.

Because for all the incredible milestones and enviable firsts that Facebook has achieved over the years, it hit an ignominious one Thursday. In the wake of a tough earnings call--heck, a nearly existential one, perhaps--Facebook's stock dropped like a rock.

Investors are spooked. Insiders are cashing out. And the company now has the distinction of having lost $120 billion in one day--more than any company has ever lost in a single day before.

To stop the bleeding

Few companies are as tied in public perception to their founder and CEO the way Facebook is.

It's extraordinary that the teenager who launched the company 14 years ago remained in control. But like the captain of a ship, Zuckerberg is ultimately responsible for everything--doubly so because of Facebook's dorm room origin story.

I am no hater when it comes to Facebook. Regular readers will know that I got together with my wife because of the platform. And as a marketer and writer, I've personally made a lot of money as a result of Facebook's success: a tiny amount compared to Zuckerberg, obviously, but believe me--enough to be very grateful that it exists.

That said, it's the crucial moment. To stop the bleeding, right the ship, and whatever other cliché you want to use, Zuckerberg--and mainly Zuckerberg alone--has to stand up and act.

If he wants a road map, here are five steps. They're easy to describe, but hard to actually do. But they're also the test of true leadership.

1. He needs to take responsibility.

Zuck has a head start on this one. He's clearly decided that Facebook's message to its user base has to be that it takes responsibility for the recent scandals--from Cambridge Analytic on down. That's why in a recent interview he managed to utter that word, "responsibility," a total of 35 times.

The only problem: It sounds a bit stilted. Now, he needs to communicate, on a visceral level, that he understands the dark side to the entity he launched. And that he's on it.

2. He needs to talk directly.

I mean, he has to talk to the users. Not a little red notice next to the globe on your FB notifications. Not a weird little ad in the news feed.

No. Zuckerberg needs to do something I'm not aware he's ever done: direct message every single person on the platform, explaining what happened, why it got past him and his team, how he takes responsibility, and what he plans to do going forward.

3. He needs to show some emotion.

I don't know if Zuckerberg is an emotional person. His public persona doesn't suggest that he is. But, my God, if ever there was a time.

Look. He created this really cool thing that connected people like nothing else ever did. And then: People hacked it. Personal information was misappropriated. Foreign governments, according to our intelligence agencies, tried to hack our elections.

Zuckerberg needs to show that he's angry.

Angry and offended. In control, perhaps, but motivated to act.

Otherwise, if not from him, where's the passion going to come from?

4. He needs to make a sacrifice.

I wrote last night about the obscene amounts of money that Zuckerberg "lost" as Facebook's stock cratered.

But even after a catastrophe, he's still the sixth-richest person in the world. No matter what happens, he's going to be wealthier and flat-out better off than almost every other person on the entire planet.

If he wants to transcend that, he has to show some sacrifice.

I'm not sure exactly what form it would take. But I can tell you that if I woke up tomorrow and realized Zuckerberg had quickly dedicated say, $25 billion (a massive number but still only one-third of his net worth) to combating foreign interference in American elections, I'd sure as heck take notice.

5. He needs to ask for a vote of confidence.

In many systems of government, when a leader faces a crisis, he or she (or the opposition) can call for a vote of confidence. That's what Zuckerberg needs here.

He's been CEO of Facebook for 14 long years, and he has a CEO waiting in the wings: Sheryl Sandberg. 

So, why not step aside? Why not let someone else take the reins? He needs to take the risk. If you love someone, the saying goes, set them free.

Somehow, Zuckerberg has to find a way to do this with Facebook. The only way to stay in control, and to lead effectively, is to be willing to give it up.

If people believe he can lead now, great. If not, be willing to step aside. It's the only way.