By Phil Cornell Students at Columbia University protesting a war they consider unjust and intolerable? That must sound awfully familiar to Mark Rudd, who more than a half-century ago similarly confronted authority while a student at the Ivy League school and can still sound like a radical firebrand. “In 1968 and students right now are reacting to a terrible moral tragedy, a crime, a catastrophe, disaster,” said Rudd by phone Tuesday, the 56th anniversary of the student takeover at Columbia. “In Gaza, 34,000 people, mostly innocent civilians, including lots of children, are being murdered. In V…