A federal judge in San Diego yesterday upheld the constitutionality of the new federal sentencing guidelines, ruling in direct conflict with an earlier decision by another judge there that the commission that wrote the guidelines violated the doctrine of separation of powers.

In a 32-page opinion, U.S. District Court Judge William B. Enright rejected arguments that the guidelines are unconstitutional because the commission is part of the judicial branch, rather than the executive, and because three sitting federal judges are among the seven commissioners.

Enright's ruling is the first written decision upholding the constitutionality of the guidelines, which took effect Nov. 1 and apply to crimes committed after that date. In an opinion last month, his colleague on the district court in San Diego, Judge Rudi M. Brewster, found the guidelines invalid because the membership of U.S. Sentencing Commission violated the mandate of separation of powers.

Two other San Diego judges later joined Brewster's ruling in oral comments from the bench, while another judge said from the bench that the guidelines are constitutional.

The trial-level federal court in San Diego has been ruling on the cases because the federal public defender there has been pressing the argument against the guidelines.