WASHINGTON — The Supreme Court, unanimously reversing the 9th Circuit Court of Appeals for the third time in a week, ruled Monday that state prisoners have no constitutional right to be paroled. The decision rebuked the San Francisco-based appeals court for ordering the parole of several inmates who had been convicted of murder or attempted murder.

All three opinions that were overturned in the last week were written by veteran liberal Judge Stephen Reinhardt from Los Angeles.

In last week’s ruling, the justices said the 9th Circuit was wrong to reverse the convictions of two men who had been convicted of murders many years before. Reinhardt’s opinion faulted the defense lawyers for the two men.

In Monday’s decision, the justices said Reinhardt and the 9th Circuit were wrong to second-guess the California parole board and the state courts for denying parole to Damon Cooke of Los Angeles, who was convicted of the attempted murder of a friend in Berkeley in 1991. Cooke was given a term of up to life in prison, and the parole board said he “would pose an unreasonable risk to society if released from prison.”

Cooke appealed and lost in the state courts, but last year, Reinhardt and the 9th Circuit said parole officials did not have enough evidence to justify denying parole to Cooke.

The California attorney general’s office appealed and, without hearing arguments in the case, the Supreme Court reversed the 9th Circuit in an unsigned opinion. “There is no right under the federal Constitution to be conditionally released before the expiration of a valid sentence, and the states are under no duty to offer parole to their prisoners,” the justices said in Swarthout v. Cooke. “That should have been the beginning and the end” of the matter in the federal courts, they said.

California prosecutors said that since Reinhardt’s ruling last June, several dozen state inmates had won parole from federal judges, and several hundred more appeals were pending.

Still pending before the high court is California’s appeal of a three-judge ruling that would require the state to release as many as 40,000 inmates to relieve overcrowding. Reinhardt was one of the three judges who handed down the disputed order.

In other decisions Monday:

The justices expanded slightly the protections granted by the Civil Rights Act and said relatives and close friends are shielded from retaliation if the person close to them complains of discrimination.

In the case before the court, Miriam Regaldo accused her employer of sex discrimination. Three weeks later, her fiance Eric Thompson, a fellow employee, was fired. Thompson sued his employer under the part of the Civil Rights Act that forbids retaliation for filing a complaint, but the U.S. appeals court in Cincinnati ruled he was not covered by the law. The high court unanimously disagreed in Thompson v. North American Stainless. “Hurting him was the unlawful act by which the employer punished her,” wrote Justice Antonin Scalia.

The justices also restored a $625,000 verdict won by a female prisoner in Ohio who said two prison officials had refused to protect her from a repeat sexual assault by a guard.