It takes an ad hoc “war room” at Facebook headquarters with dozens of staff members working round-the-clock shifts. It takes hordes of journalists and fact checkers willing to police the platform for false news stories and hoaxes so that they can be contained before spreading to millions. And even if you avoid major problems from bad actors domestically, you might still need to disclose, as Facebook did late Tuesday night, that you kicked off yet another group of what appeared to be Kremlin-linked trolls.

I’ve experienced Facebook’s fragility firsthand. Every day for the past several months, as I’ve covered the midterms through the lens of social media, I’ve started my day by looking for viral misinformation on the platform. (I’ve paid attention to Twitter, YouTube and other social networks, too, but Facebook is the 800-pound gorilla of internet garbage, so it got most of my focus.)

Most days, digging up large-scale misinformation on Facebook was as easy as finding baby photos or birthday greetings. There were doctored photos used to stoke fear about the caravan of Latin American migrants headed toward the United States border. There were easily disprovable lies about the women who accused Justice Brett M. Kavanaugh of sexual assault, cooked up by partisans with bad-faith agendas. Every time major political events dominated the news cycle, Facebook was overrun by hoaxers and conspiracy theorists, who used the platform to sow discord, spin falsehoods and stir up tribal anger.

Facebook was generally responsive to these problems after they were publicly called out. But the platform’s scale means that even people who work there are often in the dark. Some days, while calling the company for comment on a new viral hoax I had found, I felt like a college R.A. telling the dean of students about shocking misbehavior inside a dorm he’d never visited. (“The freshmen are drinking what?”)

Other days, combing through Facebook falsehoods has felt like watching a nation poison itself in slow motion. A recent study by the Oxford Internet Institute, a department at the University of Oxford, found that 25 percent of all election-related content shared on Facebook and Twitter during the midterm election season could be classified as “junk news.” Other studies have hinted at progress in stemming the tide of misinformation, but the process is far from complete.