LOS ANGELES -

In a major blow to teachers' unions, a Los Angeles judge ruled today that state laws governing teacher tenure are unconstitutional, saying students and teachers alike are "disadvantaged'' by the statutes.

Los Angeles Superior Court Judge Rolf M. Treu issued an injunction blocking tenure laws for public school teachers, but also placed a stay on the ruling pending an appeal.

In his ruling that followed a lengthy non-jury trial, Treu ruled that the state's system governing tenure and the hiring and firing of teachers "disproportionately affect poor and/or minority students.'' He wrote that "both students and teachers are unfairly and unnecessarily disadvantaged by the current permanent employment statute.''

The lawsuit was filed in May 2012 on behalf of nine young plaintiffs, alleging the laws violate students' constitutional rights to an equal education. The suit named the state and two teacher unions that later intervened as defendants, the California Teachers Association and the California Federation of Teachers.

Plaintiffs' attorney Theodore Boutrous argued during the trial that five laws should be deemed unconstitutional, saying tenure laws made it too time-consuming and expensive to dismiss ineffective educators.

"Teaching is the one profession in the world where you cannot tell a person they are not doing a good job,'' he said during his closing argument.

But lawyer James Finberg, representing the teacher unions, countered that the laws help prevent teachers from being hired and retained for reasons involving favoritism and politics. He said that in as little as three months, an administrator can make a "well-informed decision'' as to whether a probationary teacher should be retained.

"The statutes should not be struck down on the basis of a handful of anecdotes,'' Finberg said.