The court ruled by 6-3 majority in favour of a Los Angeles sheriff’s deputy who was sued after not reading a Miranda warning to a hospital worker accused of sexually assaulting a patient.
Justice Samuel Alito wrote in his majority opinion that Miranda warnings, such as the “right to remain silent”, were a set of guidelines rather than a constitutional right that could result in a civil litigation against the police.
“A violation of Miranda is not itself a violation of the Fifth Amendment” Justice Alito wrote, adding that the court saw “no justification for expanding Miranda to confer a right to sue”.
The only remedy for a Miranda violation was to block the use of incriminating statements in court, the court ruled.
The court’s three liberal justices warned in a dissenting opinion that the decision would weaken Miranda rights and may encourage police to pressure people in custody.
The ruling came in the case of Vega v Tekoh, in which a patient at a Los Angeles hospital who had suffered a stroke said she had been sexually assaulted and identified hospital worker Terrence Tokah as her attacker.
Los Angeles County Sheriff’s Deputy Carlos Vega interviewed Mr Tekoh, who later signed a statement confessing to the assault.
Both sides agree that Mr Vega did not read Mr Tekoh his rights before their conversation at the hospital. But they disagree about whether Mr Tekoh was coerced into confessing.
Even with the statement used against him at trial, a jury acquitted Mr Tekoh of criminal charges.
He then sued Mr Vega, who twice prevailed at civil trials over his conduct.
A federal appeals court ruled Mr Tekoh should have another chance.
The deputy appealed to the Supreme Court, which agreed to hear the case.
A federal law known as Section 1983 allows people to sue police officers and other government workers for violations of constitutional rights.
The Miranda warning was recognised by the court in its Miranda v Arizona decision in 1966 and reaffirmed 34 years later. But at issue in Wednesday’s decision was whether it should be considered a constitutional right, or has a lesser, and less-defined status.
During arguments on the case in April, Justice Elena Kagan said she feared that if the court rules for Mr Vega, the outcome “will undermine Dickerson,” the 2000 decision that was written by the late Chief Justice William Rehnquist.
Justice Rehnquist was a critic of the Miranda decision who nevertheless said it had become embedded in American culture.
Associated Press contributed to this report