HARRISBURG, Pa. — Judicial candidates in Pennsylvania are free to discuss the issues of the day on the campaign trail, so long as they do not promise to rule in a particular way once they are elected, a federal judge has ruled.

The ruling in Pennsylvania Family Institute Inc. v. Celluci was issued last week by Senior Judge Marvin Katz of the U.S. District Court in Philadelphia. The case stemmed from a lawsuit filed in the spring by the conservative Pennsylvania Family Institute and a half-dozen judicial candidates. The defendants were individual members of the state Judicial Conduct Board and certain officials in the state Office of Disciplinary Counsel.

At issue is a provision in the Pennsylvania Code of Judicial Conduct that bars judicial candidates from promising anything more than “the faithful and impartial performance of the duties of office” and from making statements that “commit or appear to commit the candidate with respect to cases, controversies or issues that are likely to come before the court.”

The plaintiffs said the rule was unconstitutionally vague, but the judge said that when construed narrowly, the rule passes constitutional muster, allowing “[a]ny speech by a judicial candidate, short of a pledge, promise or commitment to adjudicate a particular result.”

The institute sent a questionnaire to 120 candidates for state and county judgeships, soliciting their views on issues that included abortion, gay marriage and school prayer. The plaintiffs, all Republicans running in the May 15 primary, said they wanted to respond to the institute’s survey and one from another group, but declined to do so out of fear that it would violate the rule on campaign speech.

Only 19 candidates responded to the institute’s questionnaire, according to court papers.

Katz, who also lifted a preliminary injunction that had temporarily barred enforcement of the rule, stressed that the rule is only one factor that aspiring judges must consider in deciding whether to speak out on controversial topics.

“Many candidates refused to answer those questions, because they feared their answers would force them to recuse themselves from future cases, and more importantly, cast doubt on the impartiality and integrity of Pennsylvania’s courts,” Katz wrote. He said he “wholeheartedly agreed with these sentiments.”

Michael Geer, president of the institute, said his group had not decided whether to appeal but that Katz’s ruling provided the clarity that the lawsuit sought.

“We accomplished the public good we were seeking,” he said, adding that it should make it more difficult for candidates to duck questions about their political views.

“It’s going to be tough for judicial candidates to simply hide” behind the rule, Geer said.

In explaining how the rule should be interpreted, Katz relied heavily on an affidavit from Joseph A. Massa Jr., chief counsel for the Judicial Conduct Board.

The board investigates allegations of ethical misconduct by judges and prosecutes those that result in formal charges.

Massa said he was not aware of any complaint against a judicial candidate for violating the campaign-speech rule ever being filed or investigated. He also said none of the candidates violated the rule by answering the questions in the institute’s survey.

Statements such as “I do not favor abortions” or “I favor prayer in public schools” are examples of speech that would be acceptable under the rule, Massa said. Examples of unacceptable statements include “I would not uphold a sentence of capital punishment” or “I will give jail sentences for violent crimes,” he said.

Under the ruling, the defendants are barred from advocating a broader interpretation of the rule in the future.