WASHINGTON (AP) _ The Supreme Court today made it more difficult for prison inmates to win lawsuits challenging unfit prison living conditions.

By a 5-4 vote in a case from Ohio, the justices said prisoners who claim conditions are so bad they amount to cruel and unusual punishment must prove officials acted with ''deliberate indifference.''

The dissenters said the ruling means inhumane conditions will prevail whenever officials can make a case that they lacked money to improve matters.

Rejecting arguments by the Bush administration, the court said the state of mind of officials who permit unfit prison conditions must be considered in such lawsuits.

Justice Antonin Scalia, writing for the court, said inmates must prove officials acted with deliberate indifference but - in a partial victory for the prisoners - said they need not meet a stricter standard of proving malicious intent.

Justice Byron R. White, in a partial dissent, said, ''The ultimate result of today's decision, I fear, is that serious deprivations of basic human needs will go unredressed due to an unnecessary and meaningless search for deliberate indifference.''

''Inhumane prison conditions often are the result of cumulative actions and inactions by numerous officials inside and outside a prison, sometimes over a long period of time,'' he said. ''In truth, intent simply is not very meaningful when considering a challenge to an institution.''

He was joined by Justice Harry A. Blackmun, Thurgood Marshall and John Paul Stevens.

In other action, the court:

- Ruled that Congress exceeded its authority when it helped create an agency to operate two major airports serving the nation's capital and its suburbs.

The court, by a 6-3 vote, said a federal law creating the Metropolitan Washington Airports Authority and a supervisory board in 1986 violated the constitutionally required separation of powers between the executive and legislative branches of government.

- Let stand a Chicago man's drug-trafficking conviction, rejecting arguments that his prosecution was tainted by an unlawful ''sniff'' search by a narcotics-detecting dog.

The court, without comment, turned away the appeal of Aureliano Vasquez, who contended that police sometimes need court warrants before using dogs that way.

- Rejected an appeal by six former military reservists who accused the armed forces of discharging them as they neared 20 years of service to cut their retirement benefits.

The court, without comment, let stand a ruling that the government has broad power to discharge reservists.

- Rejected the appeal of an Ohio couple who sought to continue giving their church 10 percent of their income while paying off debts under federal bankruptcy law protection.

The justices, without comment, let stand rulings that barred Stephen and Charlene Ivy of Worthington, Ohio, from including their religious tithes as reasonably necessary expenses.

In the prison case, the four dissenters joined the court in overturning a federal appeals court ruling that said inmates must prove officials acted out of malicious cruelty to win such suits.

The 6th U.S. Circuit Court of Appeals had thrown out the suit by Pearly Wilson, a prisoner in Hocking Correctional Facility in Nelsonville, Ohio.

Wilson alleged prison overcrowding, rat-infested kitchens, freezing cold in winter, scalding heat in summer and other miserable conditions.

He said the inmates were in cramped cells, subject to excessive noise, foul lavatories and housed with the physically and mentally ill.

He accused officials of violating the Eighth Amendment to the Constitution forbidding cruel and unusual punishment.

The 6th Circuit court said the state, at worst, is guilty of negligence. State officials said there is ample evidence the state tried to improve conditions at the facility.

Today's decision gives Wilson another chance to prove officials violated the Eighth Amendment. The justices ordered further lower court hearings to determine whether the officials acted with deliberate indifference.

The case is Wilson vs. Seiter, 89-7376.