WASHINGTON — A sharply-divided Supreme Court today made it more difficult for Americans to sue businesses for discrimination and retaliation, leading a judge to call for Congress to overturn the court’s actions.

The court’s conservatives, in two 5-4 decisions, ruled that a person must be able to hire and fire someone to be considered a supervisor in discrimination lawsuits, making it harder to blame a business for a coworker’s racism or sexism. The court then decided to limit how juries can decide retaliation lawsuits, saying victims must prove employers would not have taken action against them but for their intention to retaliate.

Justice Ruth Bader Ginsburg, who wrote both dissents for the court’s liberal wing, said the high court had “corralled Title VII,” a law designed to stop discrimination in the nation’s workplaces.

“Both decisions dilute the strength of Title VII in ways Congress could not have intended,” said Ginsburg, who called on Congress to change the law to overturn the court.

Karen Harned, executive director of the National Federation of Independent Business’ Small Business Legal Center, cheered the decision.

“If courts were allowed to label employees with little managerial authority as `supervisors,’ that would have substantially increased the number of frivolous lawsuits brought against small businesses and would have done little, if anything, to reduce harassment,” she said.