(On Wednesday, TechCrunch reported that Google had a similar research app, called Screenwise Meter. In a statement, Google said it was disabling the app, which it said “should not have operated under Apple’s developer enterprise program.”)

There’s no doubt that Apple took a firm stand here. But if Mr. Cook truly wants to protect Apple users from privacy-violating apps, he could remove all of Facebook’s products — including Instagram and WhatsApp — from the App Store until the company can prove, in a real and measurable way, that it cares about its users’ privacy.

Shutting off Facebook’s access to Apple devices would be a radical step, tantamount to declaring war on a major competitor. But Apple has banned developers for smaller infractions in the past. And in the absence of government regulation, there may be no other option for bringing the company to heel on privacy.

Would temporarily cutting off Facebook’s Apple apps be an effective deterrent? Absolutely. In less than a day, Apple’s move to revoke Facebook’s developer certificate has reportedly become a “critical problem” for the company’s developers. Hundreds of millions of people use Facebook through their iPhones, and without access to Apple’s App Store, Facebook would see an immediate and devastating hit to its bottom line. The ban would quickly become an existential threat, and improving privacy on its apps would become an all-hands-on-deck project for the company’s leadership.

Would it be fair? Yes. Facebook’s privacy violations over the years have been appalling, and its executives have blatantly evaded the rules that Google and Apple, the makers of the two largest mobile operating systems, have put in place to protect their users from being exploited by data-hungry app developers. In emails released late last year, Facebook executives were shown plotting to snoop on Android users’ call and text logs without triggering a permission pop-up. And Facebook’s Onavo VPN app was pulled from Apple’s App Store last year for excessive data collection.

Would cracking down on Facebook backfire on Apple? Possibly. Facebook’s apps are some of the most popular offerings on Apple devices, and without access to their Instagram and Facebook feeds, some iPhone users might get frustrated and switch to Android. But this abandonment would happen slowly, not all at once. (IPhone users could still access Facebook’s products through their mobile web browsers.) And more likely, given how heavily Facebook relies on Apple’s platform, Facebook would almost certainly blink first, and make the necessary changes to get back into Apple’s good graces.