The city teachers union has taken another step to thwart a high-profile lawsuit against teacher tenure in New York State, asking the court to throw out the suit altogether.

The United Federation of Teachers officially jumped into the lawsuit in July, but it had not spelled out its legal strategy until it filed the 53-page brief today. The brief seeks to dismiss the lawsuit — formed after a judge merged two independent challenges against teachers’ job protections — on the grounds that the people who filed it have not in fact been denied the “sound, basic education” that New Yorkers are guaranteed.

The union also claims that the plaintiffs do not have standing to bring the lawsuit. Only one of the parents participating in the suit says her child has had an ineffective teacher, and the suit does not argue that the state’s laws protected that teacher, the union notes.

The UFT also notes that the legislature and state Department of Education have already begun tackling issues related to teacher effectiveness in ways that the lawsuit does not acknowledge. The state recently rolled out a teacher evaluation system that takes student progress into account for the first time, and it also shortened the length of hearings for teachers whom districts are trying to fire.

“These proceedings reflect an inappropriate attempt by those with a special agenda to draw the judiciary into a political thicket involving political questions and public policy debates that have recently been and remain the subject of concerted and ongoing action by the legislative and executive branches of the government,” the brief reads.

The lawsuit against teacher tenure aims to replicate the outcome of the Vergara case in California, in which a judge ruled in June that the state’s job protections for teachers hurt low-income students. One of the challenges came from parents organized by the Partnership for Student Advocacy, a group headed by former CNN anchor Campbell Brown, and the other was filed by parent activist Mona Davids.

“Concerns we have about the quality of our children’s education have been ignored or denied at every level,” plaintiff Keoni Wright said in a statement referring to the union’s motion. “So it comes as no surprise that administrators and bureaucrats claim that parents — those with the largest interest in the well-being of their children — don’t have standing. This is exactly why we have turned to the courts.”

Brown said earlier this month that she is prepared for a drawn-out fight with the union and the other groups, including the state Department of Education, that are opposing her suit. “Assuming that we … get beyond a motion to dismiss, then the discovery phase begins and we’re off to the races,” she said.