On his daily radio and television shows, Glenn Beck has elevated once-obscure conservative thinkers onto best-seller lists. Recently, he has elevated a 78-year-old liberal academic to celebrity of a different sort, in a way that some say is endangering her life.

Frances Fox Piven, a City University of New York professor, has been a primary character in Mr. Beck’s warnings about a progressive take-down of America. Ms. Piven, Mr. Beck says, is responsible for a plan to “intentionally collapse our economic system.”

Her name has become a kind of shorthand for “enemy” on Mr. Beck’s Fox News Channel program, which is watched by more than 2 million people, and on one of his Web sites, The Blaze. This week, Mr. Beck suggested on television that she was an enemy of the Constitution.

Never mind that Ms. Piven’s radical plan to help poor people was published 45 years ago, when Mr. Beck was a toddler. Anonymous visitors to his Web site have called for her death, and some, she said, have contacted her directly via e-mail.