The Supreme Court was told this week that union contracts give employers "absolutely no excuse" to disobey a law requiring them to accommodate the religious observances of workers so long as accommodation doesn't cause "undue hardship."

Emphasizing that laws override contracts, Nathan Lewin argued for the Orthodox Jewish community that a company and a union could not make an enforceable collective bargaining agreement, for example, to sell the Brooklyn Bridge.

Justice Thurgood Marshall remarked that Trans World Airlines Co., the company in the case at issue, did not own the Brooklyn Bridge.

Neither did TWA own the rights of Larry G. Hardison, the former employee in the case who observed a Saturday Sabbath as required by his belief in the Worldwide Church of God, Lewin replied.

He argued on the side of Hardison as a friend of the court. On the other side as TWA and the International Association of Machinists and Aerospace Workers, AFL-CIO.

Reflecting the sensitive business, labor, civil rights, and religious issues raised by the case, organizations ranging from an employers' group, the Equip Employment Advisory Council to the General Conference of Seventh Day Adventists also have filed friend-of-the-court briefs.

Hardison, now of Portland, Ore., was a store clerk and a Machinist's Union member at TWA's aircraft overhaul base in Kansas City, Mo. The base operates 24 hours a day, 365 days a year, under a union agreement with rigid seniority provisions, giving senior employees first crack at having Saturdays and Sundays off.

In the spring of 1968, less than a year after being hired, Hardison told TWA that he had joined the World wide Church and wanted to be off each week from sunset Friday to sun set Saturday because "I sincerely believe this is the Sabbath and no servile work must be done then."

The company, the union and Hardison improvised arrangements that spared him Saturday work for several months. But at the end of 1968, in order to get on a day shift so he could spend evenings at home, he requested transfer to another building, knowing that this would move him from near the top of one seniority is to near the bottom of another.

In March, 1969, Hardison failed to show up for work on three Saturdays and left at sunset the following Friday. To solve the problem, he later offered to change his shift. The union also tried to find solutions. But no permanent solution was found. Finally, without Hardison filing a grievance, he was fired.

Hardison sued TWA and the union and lost in a lower court. But the Eighth Circuit Court of Appeals reversed, saying that the company had not made the reasonable accommodation to Hardison's religious practice required by the Civil Rights Act of 1964. "The company may not accept the role of a Pontius Pilate," the court said.

Wednesday, George E. Feldmiller argued for TWA that it has done its "very best" to accommodate Hardison within the contract's seniority provisions. Replying to a question by Justice Potter Stewart, he said TWA would have treated employees seeking to be off on Sundays - the Sabbath for most Americans - "exactly the same."

For Hardison, William H. Pickett said that TWA had done "nothing of substance" to reach a reasonable accommodation, such as putting Hardison on a four-day week as permitted by the contract.

For the machinists, Mozart G. Ratner said that the contract provisions are totally neutral, according discriminatory or special treatment for neither religious nor secular observances, and live up to the letter and spirit of the law.

If TWA had given Hardison Saturdays off permanently by paying someone else overtime or by replacing him with a higher-paid supervisor, it would have paid an unconstitutional "tars" to support his religion, Ratner argued.