In ruling unanimously Wednesday for five officers attached to the Central Utah Narcotics Task Force, the court also abandoned a rigid, two-step test that it adopted in 2001 to guide judges in assessing alleged violations of constitutional rights.

Trial and appellate judges "should be permitted to exercise their sound discretion" in evaluating such claims, Justice Samuel Alito said in his opinion for the court.

Under the 2001 ruling, courts first had to determine whether an action amounts to a violation of a constitutional right and then decide whether the public official, often a police officer, should be immune from the civil lawsuit.

The case grew out of a search of the home of Afton Callahan of Millard County, Utah, in 2002.

An informant contacted police to tell them he had arranged to purchase drugs from Callahan at Callahan's trailer home.

Wearing a microphone provided by police, the informant entered the trailer and signaled police that a deal had been made. They entered the trailer without a warrant and arrested Callahan on charges of possession of methamphetamines.

Utah courts ruled that the evidence that was seized from Callahan's home could not be used against him. Other courts have allowed prosecutions to go forward under similar circumstances.

Callahan later sued the officers for violating his constitutional rights. A federal judge ruled the officers could not be sued because there is disagreement in the courts over whether the search was illegal.