The Supreme Court yesterday declined to review the legality of the FBI's Abscam undercover operation and left intact the Abscam convictions of four former members of Congress.

The court acted without comment as it rejected appeals from former representatives Raymond F. Lederer (D-Pa.), John M. Murphy (D-N.Y.), Michael O. Myers (D-Pa.) and Frank Thompson Jr. (D-N.J.), who now face prison terms and fines.

The justices also declined to consider appeals from three lesser known Abscam defendants: former mayor Angelo Errichetti of Camden, N.J., and Philadelphia lawyers Louis Johanson and Howard Criden.

Despite the long-running debate over the propriety of the operation and a request by the American Civil Liberties Union for Supreme Court review, no justice displayed any interest in the cases by publicly dissenting from yesterday's action.

The defendants had sought review on a variety of grounds, including a claim that the "sting" operation involved illegal entrapment and that the government should be barred from investigating members of Congress unless it has solid reason to suspect them of crimes.

The Justice Department told the court that all of the contentions were "without foundation in the law" or "plainly insubstantial" and of "insufficient importance" to warrant Supreme Court review. The government said that Congress could act to amend federal criminal laws if it disapproves of how the Abscam probe was handled.

The officials were snared through the use of FBI agents posing as Arab sheiks and middlemen seeking special favors from the congressmen in return for cash bribes.

Hidden cameras and microphones recorded the transactions and provided the evidence for the convictions.

Three other members of Congress--former representatives Richard Kelly (R-Fla.) and John W. Jenrette Jr. (D-S.C.) and former senator Harrison A. Williams Jr. (D-N.J.)--also were caught in the Abscam net. Their appeals could give the court another opportunity to rule on the issues. By turning down the appeals yesterday, as well as earlier appeals by two former Philadelphia city councilmen, the justices have shown little or no interest in the questions, however.

The ACLU, in a friend-of-the-court brief, had told the justices that the Abscam approach, if left untouched by the courts, gives authorities "at every level carte blanche to engage in intrusive undercover activity reaching the verge of entrapment with no judicial controls."

The ACLU aruged that the government should have "probable cause" to suspect members of Congress of crimes or of a predisposition to commit a crime before unleashing such a far-reaching investigation.