This expansion of employee rights stands in sharp contrast to a series of pro-business rulings limiting the rights of workers that were made last year by the Supreme Court.

Tuesday's decisions do not amount to a sharp change in the law. Most civil rights laws already protect employees against being punished for complaining of bias based on their race, religion, gender, national origin or age.

However, in both cases the court read an older law broadly to give employees more rights to sue for discrimination.