The city commissioned a granite monument depicting a soldier kneeling in front of a grave with a cross on top of it. U.S. District Judge Stephen Wilson ruled the monument sends an "unmistakably religious message" and violates the constitutional separation of church and state.
Wilson granted a preliminary injunction against the statue's installation. A trial for a permanent injunction is set for September.
Two Lake Elsinore residents represented by the American Humanist Association challenged the monument, which is located at the entrance to Diamond Stadium, a minor league baseball park.
"The legislative history and the comments of the city's elected leaders leading up to approval of the (monument) would lead a reasonable observer to believe that the monument endorses Christianity and Judaism," Wilson wrote.
The monument design depicts a soldier kneeling before rows upon rows of crosses, like those erected over many of the graves of servicemen killed at Omaha Beach.
However, Wilson found the argument unpersuasive in the face of statements by city leaders and a representative of the local historical society -- all of whom avowed their faith during public meetings.
"At least three council members made specific statements that they wanted to keep the Latin cross as part of the monument because of its religious symbolism," said Wilson.
The Associated Press and City News Service contributed to this report.