A Facebook co-founder has called on the U.S. government to break up the social network, saying it’s become far too powerful and that Mark Zuckerberg must be held accountable. Chris Hughes, who started Facebook with Zuckerberg at their Harvard dorm, wrote in a New York Times opinion piece published Thursday that he feels “anger and responsibility” over Facebook’s response to “sloppy privacy practices... the slow response to Russian agents, violent rhetoric and fake news; and the unbounded drive to capture ever more of our time and attention.” He defended Zuckerberg personally, calling him a “good, kind person,” but said: “I’m angry that his focus on growth led him to sacrifice security and civility for clicks.” Hughes added to calls from Sen. Elizabeth Warren and Sen. Ted Cruz, who have called for regulation, saying: “We are a nation with a tradition of reining in monopolies, no matter how well-intentioned the leaders of these companies may be. Mark’s power is unprecedented and un-American. It is time to break up Facebook.”