When can workers sue against acts of retaliation by employers? Two cases slated for hearing this week

Employer retaliation cases reach U.S. Supreme Court "... Tuesday, the high court will examine whether a US postal worker can claim retaliation in a lawsuit under the Age Discrimination in Employment Act because she says her supervisor refused to let her return to her old job because he didn't like her personally. Instead, he hired a younger, less experienced worker. ..." [Reference: www.csmonitor.com]