"The ability to carry out the harassment is implicated in that the victim will lack the same ability to resist the harassment or to report it," Srinivasan said.

Justice Elena Kagan raised a hypothetical of a professor who subjects his secretary to a "complete hostile work environment on the basis of sex," but has no ability to hire or fire her.

"It's actually more difficult for the secretary to complain about the professor than it would be for the secretary to complain about the head of secretarial services" who hired her. Kagan said under the legal standard adopted by the appeals court in the Vance case, that professor would also not be considered supervisor even if he evaluates the secretary's work performance every year.

Justice Stephen Breyer suggested the more flexible legal standard adopted by the EEOC and three other appeals courts would be the way to go.

"Apparently, for about a dozen years, the EEOC has as an alternative basis for qualifying as a supervisor, that individual has authority to direct the employee's daily work activities."

The court has options for dealing with the Vance case and a decision is not expected before spring.

Several justices suggested throwing the case back to the lower courts to develop more fully who actually had a supervisory role at the Indiana university's food services division. Others were wary of adopting a broad binding rule, when such workplace disputes are all fact-specific and often do not follow traditional worker-employer roles.

The National Federation of Independent Business and the U.S. Chamber of Commerce are supporting the university. They suggest the changing economy will put companies at risk when determining managerial duties.

"This is consistent with workplaces across America today, where jobs are less hierarchical, more collaborative, and so where you have got more senior employees by virtue of their experience or job title, just a paper title, are in a broad sense team leaders of the like in the workplace," said Gregory Garre, representing the university. "That doesn't mean they are supervisors in any traditional sense."

The AARP and National Partnership for Women & Families are backing Vance. Those groups worry restricting who qualifies as a supervisor would allow business to give hiring and firing power to as few people as possible, to limit liability. They said that would leave the law "toothless."

The case is Vance v. Ball State University (11-556).