WASHINGTON, Apr. 17 — The U.S. Supreme Court Monday let stand a controversial lower-court ruling that California officials contend may open the prison doors for convicted murderer Charles Manson.

The ruling, which the U.S. Ninth Circuit Court of Appeals in San Francisco handed down last year, overturned the 1971 burglary conviction of Lawrence S. Bittaker because California courts had denied him the right to be his own lawyer.

A few days before leaving office, former California Attorney General Evelle Younger warned the Washington high court that Manson and other convicts might take advantage of the Bittaker decision if it were allowed to stand.

“The effect on the administration of justice in California could potentially be catastrophic,” he declared.

Younger noted that Manson, in appealing his convictions in the Tate-LaBianca and Hinman-Shea murders, has argued that he was denied the right to represent himself during the trial proceedings.

The U.S. Supreme Court ruled in a 1975 case that criminal defendants have a constitutional right to self-representation in state prosecutions. The justices, however, failed to spell out whether that decision could be applied retroactively in cases like Manson’s. In the absence of a clarification, there has been a division of opinion on the retroactivity question between federal circuits and among state courts.

Younger’s successor, state Attorney General George Deukmejian, also strongly appealed to the nation’s highest tribunal to settle the issue in the Bittaker case.

But in a brief order, without any elaboration, the justices rejected the Younger-Deukmejian appeals, thus letting stand the Ninth Circuit’s ruling.

The high court, however, still could step in at some future time should Manson embark on the same legal track as Bittaker.

Bittaker, convicted of burglary in Los Angeles, lost several appeals before the Ninth Circuit approved his habeas-corpus petition last summer.

The appellate court held that it had recognized the right to self-representation in state criminal trials in 1969 — six years before the U.S. Supreme Court — and thus didn’t even have to rule on the issue of retroactive application of the 1975 national landmark decision.

Throughout the pleadings before the Ninth Circuit, state officials kept waving Manson as a red flag.

When it handed down its ruling last August, the appellate court strongly chided Younger for using this argument.

“The state mentions several times that one of its prisoners who may benefit from the (1975) decision is Charles Manson,” the Ninth Circuit observed. “We do not encourage this type of advocacy. A federal court must make its decisions in accord with the Constitution and the laws, without regard to the notoriety of parties or non-parties.”

Last January, Younger filed an appeal with the Supreme Court in which he blasted the Ninth Circuit for creating “a new standard disruptive of the criminal justice system of California.” He also made it plain that he owed nobody an apology for raising the potential implications for Manson.

“The fact that Charles Manson and others (whether notorious or not) could possibly benefit if there is retroactive application of the (1975) rule is of legitimate concern to the State of California as regards the effect retroactivity would have upon the administration of justice within its borders,” he declared.

In their unsuccessful appeals, Younger and Deukmejian asked the high court to:

• Order the Ninth Circuit to decide self-representation cases on the basis of the Supreme Court’s 1975 decision and not on the basis of its own earlier precedent.

• Decree that the 1975 decision could not be applied retroactively.

• Instruct lower courts that conviction still could be upheld if the denial of self-representation amounted to a “harmless error” within the total context of the trial.

Deukmejian backed up Younger’s appeal with two petitions of his own. Last month, he informed the justices in Washington that the Ninth Circuit, in a February decision, had again upheld an appeal based on self-representation claims in a case involving voluntary manslaughter, assault with 6 deadly weapon and sale of cocaine.

By LEO RENNERT