The battle for privacy of Apple (AAPL), Facebook (FB) has just begun

It’s hard to identify exactly where things went wrong with Facebook and Apple, but like so many relationships that have gone bad, the first signs of real problems seemed brittle. In March 2018, Facebook Inc. he was in the middle of a scandal related to the political consultancy Cambridge Analytica and was facing serious questions about its management of the personal data of its users. Asked an MSNBC commenter Apple Inc. CEO Tim Cook what would he do if he were in the shoes of Facebook CEO Mark Zuckerberg. “I wouldn’t be in that situation,” Cook said.

A week later, Zuckerberg hinted that Apple’s products were only for “rich people.” Apple then showed a feature to help phone users reduce the time spent on apps. “If you see an app where you might want to spend a little less time, you can set your own limit,” an Apple executive said as the Instagram app popped up on a big screen behind it.

Competition in Silicon Valley can be brutal, but for much of the past decade, Apple and Facebook have shared a mutually beneficial, if not always friendly, relationship. Facebook relies on Apple iPhones to reach millions of users and Apple needs the very popular Facebook apps on its phones to keep people from going to competing platforms. Both companies have thrived since the launch of the iPhone and, for the most part, have not created products that compete directly.

But Facebook and Apple are on a collision course. His competence in messaging has heated up for years. Facebook focuses on products that are too on Apple’s roadmap, such as virtual and augmented reality headphones. “Every time we see Apple as one of our biggest competitors,” Zuckerberg told analysts in January. “Apple has every incentive to use its dominant platform position to interfere with the operation of our applications and other applications, which they usually do to favor theirs.”

The dispute has escalated rapidly due to Apple’s upcoming update to the software that powers its iPhones, which includes the requirement that developers obtain explicit permission to collect certain data and track user activity through apps and websites. Such a measure could undermine the effectiveness of Facebook-specific ads. In December, Facebook posted full-page ads in a trio of American newspapers saying they were “defending Apple for small businesses everywhere” opposing the changes, which it describes as an abuse of market power. Facebook is considering filing an antitrust lawsuit against Apple, according to someone familiar with the company’s thinking.

Apple says the software update will provide users with more clarity about who collects their data and why. He describes privacy as a “fundamental human right” and his track record on the issue is a way to differentiate himself. Google from Alphabet Inc., which turns Android into the software that powers most non-Apple smartphones.

Cook seemed take a photo on Facebook on January 28 at the online conference on computers, privacy and data protection. “If a company relies on misleading users, on data mining, on options that are not options at all, then it doesn’t deserve our praise, it deserves reform,” he said. Cook added that some social networks facilitate the spread of dangerous misinformation and conspiracy theories for user engagement. “It has taken a long time to stop pretending that this approach carries no cost: polarization, lost trust, and, yes, violence,” he said.

Discussions between the two companies about the software update have been unproductive, says Graham Mudd, vice president for Facebook ads and commercial product marketing. He says attempts by Facebook and others to discuss the software update with Apple have “failed.” “Apple did not respond at all or with any degree of collaboration.”

The recent flareup now focuses on drafting the pop-up window asking iPhone users to decide whether to allow tracking. Facebook executives are worried that Apple will frame the election in an alarmist way, prompting users to refuse tracking. Facebook chief financial officer Dave Wehner told analysts he expects “high shutdown rates” for Apple’s application, and Facebook has said those changes will affect its business in the future. It plans to address Apple’s request with its own messages, framing advertising as a way to have a better Facebook experience and support companies that rely on specific ads for sales.