Raven v. Deukmejian
The proposed measure contained a section that provided that certain criminal law rights "shall be construed by the courts of [California] in a manner consistent with the Constitution of the United States" and that the state constitution "shall not be construed to afford greater rights" than those afforded by the federal constitution.
The court determined that the proposal "would have fundamentally changed and subordinated the constitutional role assumed by the judiciary in the governmental process." In other words, the amendment would affect a core function of one of the three branches of government.
The court, noting this, decided to order the amendment not to appear on the ballot because it would have amounted to a "revision" of the constitution, not an amendment.