Last month, the Trump administration announced that it would halt its policy of separating young asylum-seekers from their parents. For those Americans angered by their government’s cruel treatment of children as young as a few months old, this was a hard-fought victory. It came only after relentless lobbying of Congress; after the defection and shocking testimony of Department of Homeland Security contractors; after a torrent of heartbreaking images and videos and the work of a legion of activists, who shut down ICE facilities and even chased senior Trump officials from restaurants.

WIRED OPINION ABOUT Emerson T. Brooking (@etbrooking) is a Washington, D.C.-based writer. Peter Warren Singer (@peterwsinger) is strategist at New America. They are the authors of LikeWar: The Weaponization of Social Media, to be published in October 2018.

The sinew that bound these efforts together was social media. More specifically, it was Twitter. Although only about one in five Americans use the fast-moving, foul-mouthed platform, it has become the cornerstone of modern US politics. It is where journalists gather facts and where the president puts his brain. It is where stories gather viral momentum before breaking out into the mainstream. Increasingly, it is also a battlefield, where competing armies of activists battle it out in “like wars,” seeking to define a contentious issue one hashtag at a time.

But Twitter also has administrators: a small group of real and fallible human beings. And this is where the trouble starts. In their efforts to disrupt the world, the masters of Silicon Valley are finding it harder and harder to stand apart from the politics of it.

Two incidents of Twitter policy-making stand out amid the fierce online lobbying effort against forcible family separation. The first came when software developer Sam Lavigne created a database of 1,500 ICE agents, drawn from publicly available data on LinkedIn, as well as a Twitter bot to push their personal information out to the world. Lavigne’s project was quickly banned for “doxing”—the sharing of an unwilling party’s personal information.

The second incident came when journalists at the left-leaning Splinter news organization acquired and published the cell phone number of Stephen Miller, a senior White House advisor and gleeful foe of immigration. The journalistic outlet’s Twitter account was promptly deactivated by administrators, effectively put in “Twitter jail.” As other Twitter users shared or retweeted the number, their accounts were also deactivated.

Soon enough, user accounts were being deactivated for simply sharing a link to the Splinter story—the kind of escalation typically used to block the spread of terrorist propaganda. Eventually, users were deactivated for merely noting the deactivation of other users. In an ironic twist, alt-right activists—many previously banned from Twitter for their embrace of violent white nationalism—returned to the platform long enough to help hunt down and report the offending users.

Neither of these events meant much for the millions-strong struggle to end the Trump administration’s internment of children. But to those of us who study Silicon Valley's growing role in politics, they signal a great deal. They mark the most prominent occasions that Twitter—a service born from the progressive, free-speech ideals of early internet culture—has used its power to stymie activists on the left. That it comes during protests against 21st-century internment camps makes it all the more striking.

Although the founders of Twitter and all such services claim to administer their platforms as impartial observers, this was never really true. This small club of Silicon Valley titans has rapidly accumulated so much political power that any decision they make about the content that transits their platforms—even the absence of a decision—has a clear social impact. History would have taken a different course if Facebook had not hesitated to police viral falsehoods and Russian disinformation offensives until after the 2016 election, or if YouTube had not taken years to seriously study how its algorithms steered users toward terrorist content.

And when Twitter leaps to vigorously safeguard the privacy of government agents and high-level administration officials—the exact kind of protection it has been slow or unwilling to extend to journalists under similar threat—that decision also carries weight. It joins a pattern in which Twitter has prostrated itself to placate far-right media personalities, or looked past its own rules to justify playing host to the toxic tirades of the 45th president. Through these choices, a platform built to empower the crowd is increasingly becoming a sanctuary for the powerful.