a was serious enough to allow a lawsuit against the officer who led a team of people on a fruitless hunt for illegal automatic weapons.

Officers are ordinarily immune from lawsuits over their conduct on duty, but the high court has made exceptions when they violate someone's constitutional rights.

``It is incumbent on the officer executing a search warrant to ensure the search is lawfully authorized and lawfully conducted,'' Justice John Paul Stevens wrote in the decision. ``Even a cursory reading of the warrant in this case - perhaps just a simple glance - would have revealed a glaring deficiency that any reasonable police officer would have known was constitutionally fatal.''

Bureau of Alcohol, Tobacco, Firearms and Explosives Agent Jeff Groh went to the ranch of Joseph and Julia Ramirez armed with a search warrant that did not list any items officers were searching for, Stevens said.

The four justices in dissent said he should have been forgiven the clerical mistake.

``We all tend toward myopia when looking for our own errors. Every lawyer and every judge can recite examples of documents that they wrote, checked, and double-checked, but that still contained glaring errors,'' Justice Anthony M. Kennedy wrote, joined by Chief Justice William H. Rehnquist.

Justices Antonin Scalia and Clarence Thomas said the search was not unconstitutional.

Richard Cordray, the attorney for the agent, said officers sometimes make mistakes but they should not face personal lawsuits over them. ``It clearly is going to happen as law enforcement personnel are chasing down many investigations, juggling a lot of balls,'' he said.

A federal judge had dismissed the lawsuit against Groh, but the San Francisco-based 9th U.S. Circuit Court of Appeals ruled that the officer violated the Fourth Amendment's guarantee against unreasonable searches and seizures. The Supreme Court upheld that decision, sending the case back to Montana for the family to pursue their claims.

Agents had gotten a tip that the family had automatic weapons, grenades, a grenade launcher and a rocket launcher on their property south of Butte, Mont.

The search yielded none of those things, and no charges were filed.

``I hope that officers all over the country realize they cannot ignore the Constitution and these rules,'' said W.G. Gilbert III, a former prosecutor who represented the family. ``They have a duty to the citizenry to do this right. Particularly in these days when many feel the country is under attack, rights are more important than they are other times.''

The case is Groh v. Ramirez, 02-811.

On the Net:

Supreme Court: http://www.supremecourtus.gov/

The court opinion: http://wid.ap.org/documents/scotus/040224groh.pdf

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