Margaret Sullivan: Defend First Amendment principle. CNN should sue Trump for revoking press pass

CNN White House correspondent Jim Acosta is a smart, tough reporter. He can also be a grandstander who seems to thrive on conflict with President Donald Trump, and doesn't always know when to stop his aggressive questioning.But whether you like Acosta's style, it's clear the White House crossed a bright line Wednesday when it took away Acosta's "hard pass," which allows him the access he needs to cover the White House.That action amounts to punishing a member of the press for doing his job of in