The case before the justices comes from Minnesota, but any final decision will affect all 38 states that elect judges.
Figures supplied by the Justice at Stake Campaign, an organization of state judges promoting campaign funding reform and other measures, show how widespread the impact of Tuesday's case might be.
The Minnesota ban is based on a 1972 model code created by the American Bar Association, which is equivalent to an ABA model code set up in 1990.
Judicial conduct codes in 34 of the 38 states contain provisions from the 1972 or 1990 codes, the judicial organization said, while the four others contain different language that essentially imposes the same restriction.
The issue in the case before the Supreme Court, Republican Party of Minnesota vs. Kelly, also affects the highest state courts.
"In 29 of the 33 states where supreme court justices are being elected this year," Justice at Stake said, "the decision in Republican Party of Minnesota vs. Kelly could rewrite the rulebook on what judges can say during campaigns."
The debate is causing heat in judicial campaigns, where candidates often want to announce their positions on such issues as abortion in order to energize a particular constituency.
Justice at Stake said its recent survey of 2,428 state judges shows 55 percent believe the tone and conduct of judicial elections was getting worse.
In the case before the Supreme Court Tuesday, the Minnesota Code of Judicial Conduct bans specific speech by candidates for elective judicial office.
Canon 5 of the code forbids judicial candidates from attending and speaking at partisan political gatherings; identifying their membership in a political party; seeking, accepting or using a political party endorsement; announcing their views "on disputed legal or political issues"; personally soliciting campaign contributions, and authorizing or permitting anyone to do those things on the candidates' behalf.
Gregory Wersal, a Minneapolis-area attorney and longtime member of the state Republican Party, ran unsuccessfully for the office of associate justice of the Minnesota Supreme Court in 1996 and 1998.
Because new revisions of the code in 1996 created apparently contradictory canons, Wersal, his wife and members of his campaign committee spoke at Republican Party meetings as part of his 1996 campaign, identifying the candidate as a member of the GOP and saying he favored a strict interpretation of the Constitution.
They also distributed campaign literature criticizing several state supreme court decisions on abortion, crime and welfare, saying they disregarded the state Legislature and "common sense."
Wersal's campaign also unsuccessfully tried to get an endorsement from the Republican Party.
In May 1996, a delegate to the Republican district convention filed an ethics complaint against Wersal with the state Lawyers Board, but the complaint was dismissed.
After the Minnesota Board of Judicial Standards revised the canons to end the apparent contradiction in the code -- and the Lawyers Board told him it would now enforce Canon 5 -- Wersal, several other candidates and the Republican Party of Minnesota filed suit in federal court against the restrictions.
A federal judge upheld the restrictions, saying they served to keep the state judiciary impartial. When a federal appeals court affirmed the judge, Wersal and the party asked the Supreme Court of the United States for review.
Speaking for Wersal and the party Tuesday, Terre Haute, Ind., attorney James Bopp Jr. told the justices, "When a candidate's speech is severely restricted, the people are denied the chance to make an informed choice."
Bopp said the Minnesota restrictions are too vague to be constitutional, but conceded under questioning from Justice Antonin Scalia that a judicial candidate could be constitutionally banned from commenting on cases that could be brought before him as a judge.
Speaking for the state, Minnesota Solicitor General Alan Gilbert said, "The (existing) rule only restricts judges candidates from publicly making known how they would decide issues that would come before them as judges."
Gilbert cited Wersal's comments as an example.
"A candidate can, as Wersal did, criticize a prior decision of the court," Gilbert said. "What a candidate cannot do is say, 'Once I am elected, I am going to overturn this decision.'"
That assertion brought skeptical comment from several members of the court, including Chief Justice William Rehnquist and Scalia, who questioned whether there was that much of a difference between the two positions Gilbert laid out.
The Supreme Court should hand down a decision in the case within the next several months.
(No. 01-521, Republic Party of Minn. et al vs. Kelly et al.)