When Twitter TWTR went through its first round of layoffs a year ago, it looked like the company was shedding a layer it didn’t need. When the San Francisco company announced a second round of layoffs last month, it appeared to be cutting dangerously close to the bone. Unceremoniously killing Vine (before entertaining offers from potential buyers)? Losing a finger.

On Wednesday Adam Bain, Twitter’s chief operating officer, announced he was leaving the company. This is the equivalent of Twitter losing its legs. In other words: Bain leaving is very, very bad for Twitter.

Here’s how bad: Bain built Twitter’s revenue model from scratch and grew the business into a $2 billion a year effort. He has been a constant throughout Twitter’s past five years of turmoil. As the company struggled through executive turnover, infighting among its product chiefs, and existential questions about what Twitter is, Bain’s team has been solid.

Under Bain Twitter’s revenue grew by nearly 100% in each of the first two years it was public. When CEO Dick Costolo stepped down and Jack Dorsey was brought in as permanent CEO, Bain was elevated from head of sales to COO. Sure, he was passed over for the CEO job, but he took it in stride. He’s a team player.

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Lately it’s become clear that Twitter’s turnaround is not going as planned. Executive turnover continues, despite promises earlier this year that it had stopped. Revenue growth has shown signs of flattening out. The company is no closer to becoming profitable. Twitter’s leaky sale process went nowhere. And Bain’s sales operations were hurt by Twitter’s most recent round of layoffs.

At a certain point, all of this struggling is coming dangerously close to rubbing off on Bain’s sterling reputation as a rock star. I don’t blame him for leaving; Twitter is a mess. Some of the remaining employees were sticking around because of Bain. His exit may cause additional turnover.

In February, Twitter painted a hopeful picture of a turnaround driven by live video and a “growth mindset.” Based the headlines since—more executive turnover, shrinking revenue growth, little user growth, and little progress on the service’s harassment problem—it’s hard to believe the turnaround has taken root.

Twitter has proven to be an essential service for many people. But if the company can’t find a buyer, can’t grow, can’t curb harassment, and can’t become profitable, perhaps it should be nationalized. Luckily for Twitter, the one person who wants it to stay alive more than anyone is about to become the President of the United States.