About 30 self-styled Nazis, buoyed by a major victory in the Illinois Supreme Court yesterday, plan to celebrate Adolph Hitler's birthday April 20 by marching through this heavily Jewish Chicago suburb in storm trooper uniforms with swastika armbands.

The march would cap a complex legal battle that has aroused strong passions nationwide and has resulted in the resignations of more than one-third of the 8,000 dues-paying members of the Illinois Division of the American Civil Liberties Union, which defended the Nazis' right to march.

In an appeal filed by the ACLU, the Illinois Supreme Court yesterday upheld the right of the Nizis to display swastikas in Skokie. The court rejected the contention of Skokie lawyers that displaying swastikas would constitute "fighting words" likely to provoke a violent reaction from spectators.

The display of swastikas "by whose engaged in peaceful demonstrations canot be totally precluded solely because that display may provoke a violent reaction by those who view it," the court said. "Use of the swastika is a symbolic form fo free speech entitled to First Amendment protections."

Justice William G. Clarg, one of seven members of the court, dissented, but did not file a written explanation of his objections.

The ruling, which overturned a July 12 Illinois appellate court injunction banning swastikas in Skokie, is a significant victory for the Nazis, but they have two more legal barriers to cross before they can march in Skokie, where 40,000 of the 70,000 residents are Jewish and at least 5,000 are survivors of the Holocaust.

First, the Nazis must successfully challenge the constitutionality of three Slokie village ordinances hastily passed last May 2 in an effort to thwart the demonstration.

The ordinances ban public demonstrations "by members of political parties wearing military-style uniforms" and the distribution of material "which promotes and incites hatred" and required persons applying for parade permits to buy insurance totaling $350,000.

Second, the Nazis must defeat an effort by the Anti-Defamation League of B'nai B'rith to obtain a new state court injunction hardly different from the one overturned yesterday by the state's highest court.

No appeals are expected after the pending cases are decided.

Frank Collin, the self-styled Nazi who touched off the controversy, was reported out of town yesterday and could not be reached for comment.

Mike Whalen, a "storm trooper" in Collin's organization, said the group expects the legal obstacles to be cleared before April 20, the 89th anniversary of Hither's birth.

Sol Goldstein, a Skokie manufacturer and Holocaust survivor who is the plaintiff in the Anti-Defamation League's injunction petition, reacted angrily to the news of yesterday's decision.

"I think the swastika is a symbol of the German Nazi Party and a slogan to kill and annihilate the Jewish people," Goldstein said. "It is not a symbol of free speech. It is a symbol of genocide."

David Goldberger, the jewish ACLU lawyer who defends the Nazis, said: "We regret the enormously troubled feelings that this generates in the Jewish community. This is not the kind of decision that leaves one dancing in the streets, but the danger to the First Amendment raised in this case was too great for us to stand by silently."