Judge Rolf Treu said in a written ruling that five laws governing teacher tenure, dismissal procedures and seniority violate the state constitutional rights to equal treatment and a free public education.
Nine students who challenged the laws in a suit filed in 2012 proved that the laws "impose a real and appreciable impact on students' fundamental right to equality of education and that they impose a disproportionate burden on poor and minority students," Treu wrote.
The decision came after a two-month nonjury trial before Treu earlier this year.
"I believe in public education," Welch said. "But I also believe our public education system is failing our children because it has stopped putting their needs and their success above all else."
Treu issued an injunction barring enforcement of the laws but suspended it to give the state and two teachers' unions a chance to appeal.
The two unions, the Burlingame-based California Teachers Association and the Burbank-based California Federation of Teachers, vowed to appeal.
"Like the lawsuit itself, today's ruling is deeply flawed," CTA President Dean Vogel said. "This lawsuit has nothing to do with what's best for kids."
The unions, which were allowed to join the case to defend the laws, argued during the trial that eliminating teachers' rights would make it harder for public schools to attract and retain good teachers.
"It is fundamentally anti-public education, scapegoating teachers for problems originating in underfunding, poverty and economic inequality," CFT President Joshua Pechthalt said of the lawsuit.
A spokesman for California Attorney General Kamala Harris, who represented state officials in the trial, said lawyers in Harris' office are reviewing the decision.
The appeal process could take a year or more. If the ruling is upheld, it would require a revamping of the teacher-tenure laws.
Treu wrote that as a judge, he had to "trust the Legislature to fulfill its mandated duty" to pass laws that are constitutional and give children an equal education opportunity.
State Superintendent of Public Instruction Tom Torlakson, who was a defendant in the case, said attracting and training talented teachers is one of the most important tasks of school districts.
"Today's ruling may inadvertently make this critical work even more challenging than it already is," Torlakson said in a statement.
Treu estimated, on the basis of testimony by state officials, that between 2,750 and 8,250 of California's 275,000 public school teachers are in a category he called "grossly ineffective."
He said the evidence that grossly ineffective teachers have a negative impact on students is compelling. "Indeed, it shocks the conscience," the judge wrote.
The five laws Treu struck down were:
* A measure that gives teachers permanent tenure after two years unless their districts tell them by March 15 of the second year that they won't be retained. That is "not nearly enough time for an informed decision to be made," the judge wrote.
* Three laws providing procedural protections for teachers whom school districts are seeking to dismiss for incompetence. The layers of procedures are so "complex, time-consuming and expensive as to make an effective, efficient and yet fair dismissal of a grossly ineffective teacher illusory," Treu said. He said trial evidence indicated that firing a bad teacher can take two to 10 years and cost a district $50,000 to $450,000.
* A last-in, first-out statute requiring that teachers must be laid off in order of least seniority. Treu said the layoff of a gifted junior teacher is a "lose-lose" situation for both that teacher and students.
Congressman George Miller, D-Martinez, the senior Democrat on the House Education and Workforce Committee, applauded the decision.
"This is an historic opportunity and a defining moment for California, one that we must not squander," he said in a statement.
"We owe it to the six million students in California's public education system to be thoughtful and deliberate and to put their needs first as we move forward," he said.
—Julia Cheever, Bay City News Service