The idea of full-time career professors is actually relatively new in America. "Usually what you found from Colonial times until well into the 20th century was a strong reliance on lecturers, tutors, instructors--a dozen different names--and these would be a kind of floating pool of talent," Dr. [John] Thelin [a historian of higher education who teaches at the University of Kentucky] said. "They were pretty expendible from year to year. It's really only with the exception of a very few institutions that you even find the term 'professor' being used much until late into the 19th century."

That's when the notion of tenure took hold. Intended to safeguard intellectual freedom, it was a direct response to efforts by wealthy industrialists (who were underwriting elite universities) to suppress their professors' populist ideas. Arthur Levine, president of Teachers College at Columbia University, likes to cite the case of a Stanford University professor, a radical sociologist named Edward A. Ross, who called for railroad systems to be owned by governments instead of private interests. The trouble was, Leland Stanford's widow headed the university's trustees; and Stanford himself, a former California governor, had amassed great wealth as a railroad builder. "The obvious remedy was to have Professor Ross fired," Dr. Levine said.

After similar arbitrary dismissals, American academe eventually adopted the German university model, with its research-oriented faculty of experts and the protection of lehrfreiheit, or 'freedom to teach,' without political restraints. Today, Dr. Thelin said, the pendulum seems to be swinging back to the more fluid system--partly because of cost, partly because of control and partly in response to changing attendance patterns, including the advent of online courses.

"The new student is no longer 18 to 22 and full time, living on campus," Dr. Levine said. "That's only about 16 percent. The new majority is older, part-time working women who want to take an occasional course when they're free. The economy is changing, so people need more and more education, but they don't need degrees. Universities are still trying to adapt to a new era."

Tenure is unlikely to become extinct, he said. For one, competative institutions will always offer such perks to top names in their field. But there is little doubt that tenure is more and more a luxury. Although 64 percent of the faculty members who retired from fall 1997 to fall 1998 had left tenured positions, only 45 percent of those who were hired were given immediate tenure or tenure-track jobs.