LOS ANGELES — The landmark court decision on Tuesday finding California’s teacher tenure laws unconstitutional is likely to lead to a flood of copycat lawsuits in other states, shifting the battleground on the issue from the legislatures to the courts.

“Almost nothing the plaintiffs raised is unique to California,” said Timothy Daly, the executive director of the New Teacher Project, which has for years pressed for revamping the way teachers are hired and fired, pushing away from tenure rules that give teachers a job for life after only a few years of proving themselves.

Those tenure rules — which teachers unions say represent important job security, and detractors say make it impossible to fire bad teachers — have been publicly debated for years and have often prevailed, particularly in states like California where unions hold sway in the legislature. But with the ruling by Judge Rolf M. Treu of Los Angeles County Superior Court that California’s tenure laws violate students’ constitutional right to an education and should be struck down, the pendulum has swung abruptly.

“Teachers feel under siege by this,” said Susan Moore Johnson, a Harvard education professor who testified for the defendants in the case. “But it’s all in the context of a lack of general support for unions and the caricature that the union has been protecting incompetent teachers. That notion is now more accepted than it ever has been, even though it is not deserved.”