Cass R. Sunstein doesn’t believe that the Internet is an absolute boon for democracy, but his first attempt at pleading his case didn’t exactly seduce the public: A comment thread dedicated to his 2001 book Republic.com ultimately got the University of Chicago law professor pasted as a Nazi and a “pointy-headed socialist windbag.” Sunstein’s crime? Ironically enough, he argued that the Internet has a bad habit of generating echo chambers where people grow increasingly extreme in their thinking. Sunstein revisits his critique in the new Republic.com 2.0, and he adds a few more qualifiers to his assertions. But he refuses to back off from his central claim that the Internet has done a better job of getting us a cheap plane ticket than a new public square. He’ll also discuss his Worst-Case Scenarios, a worthy attempt to argue how governments can better calibrate their responses to matters like terrorism and climate change. Sunstein discusses and signs copies of his work at 7 p.m. at Politics and Prose, 5015 Connecticut Ave. NW. Free. (202) 364-1919.