Pittsburgh will be among the first of many cities to feel the impact of the unexpected recent Supreme Court decision that abolished absolute immunity for municipalities whose official policies or customs may have deprived citizens of constitutional rights.

The June 6 decision reversed that part of a 1961 ruling which insulated municipal corporations from damage suits by citizens seeking to vindicate their civil rights while allowing, for the first time, such suits against employes of those same municipal corporations.

Last Monday, the court followed up by rejecting a petition by the Pennsylvania city to review a ruling by the 3rd U.S. Circuit Court of Appeals involving alleged civil rights violations by members of the Pittsburgh police department.

The case dates back to 1975, when two white police officers made an early morning stop of a car occupied by two black brothers for alleged traffic violations. The brothers are Glenn R. Mahone, 32, a lawyer, and Harvey L. Mahone, 36, an employe of the Port Authority of Allegheny County.

Because they were black, the Mahones alleged, the officers followed a common police practice in Pittsburgh by abusing them with racial epithets, beating them, filing false charges of traffic violations, and giving false testimony to convict them.

Claiming bodily injuries that required hospital treatment, as well as mental anguish, the Mahones sued the city for unspecified damages.

Their suit relied on a Reconstruction-era civil rights statute requiring the states not only to give blacks the same benefit of the laws "as is enjoyed by white citizens," but also to subject blacks "to like punishments, pains . . ."

A federal judge dismissed the suit on the ground that the 1961 Supreme Court ruling had immunized the city, but was reversed by the appeals court.

Assuming for purposes of its decision that the facts as alleged by the Mahones were true. Circuit Court of Appeals Judge Max Rosenn wrote that the law, known as section 1981, opens the city to suit because the brothers' complaint was "based not on private acts of violence, but instead on official misconduct under color of state law by the city's police officers."

Neither the Supreme Court decision endign the absolute immunity of municipal corporations nor the survival of the 3rd circuit decision is expected to deter West Haven, Conn., from seeking review of a ruling with which the 2nd U.S. Circuit Court of Appeals cleared the way for a $200,000 damage suit against the city.

The reason is that unlike the Supreme Court and the 3rd circuit, both of which relied on Reconstruction-era civil rights laws, the 2nd circuit held that the Constitution - in the 14th Amendment - allowed West Haven to be sued for alleged violations by its police department.

In the opinion for a 5-to-4 majority in the 2nd Circuit, Chief Judge Irving R. Kaufman limited the scope of the ruling to cases where a municipality is shown to be "itself a wrongdoer," that is, when municipal officials or policymaking bodies authorize, ratify or sanction "unconstitutional actions of employes."

Even so, said Circuit Judge Ellsworth A. Vangraafeiland, the majority's legal theory could undermine the financial stability of numerous communities and "benefit neither the courts nor the country."

The case involved Thomas Turpin. A few years ago, when he was a teenager, two West Haven police officers arrested him. Alleging that they had used excessive force to restrain him, Turpin sued them in federal court and was awarded $3,500.

Later, the department promoted one of the officers. This encouraged other officers "to believe that they could violate his civil rights with impunity" and let to a new arrest, he said, adding that the $3,500 award generated animosity toward him in the department.

In the opinion for the Supreme Court on June 6, Justice William J. Brennan Jr. wrote that the majority was leaving "to another day" the question of "what the full contours of municipal liability . . . may be . . ."

The contours seemed to become slightly clearer last Monday, when the court declined a petition by the New York City Transit Authority to review a damage reward against it on the ground that the authority is not a municipality, but an independent public body created by the state legislature to operate city-owned transit and immunized against suit.

But the court did agree to decide in the term starting next October two questions raised in the authority's petition: Was its denial of employment to black former heroin addicts participating in methadone maintenance programs a denial of the due process of law and the equal protection of the laws guaranteen by the 14th Amendment? Was the denial also racial discrimination in violation of the Civil Rights Act of 1964?