The decision comes after attorneys for Legal Voice, the American Civil Liberties Union of Washington and Pacifica Law Group filed a lawsuit this week in King County Superior Court on behalf of the state teachers union, a Seattle nonprofit and parents of student-athletes. The suit seeks to block the initiative before it is scheduled to take effect Dec. 3.

The state of Washington is the defendant in the case, and the attorney general’s office typically defends lawsuits against voter-approved measures. In a written statement, Brown said defending such laws is “one of the most important duties” of his office, but he also stressed that his personal views do not determine how vigorously a law is defended.

“My personal views do not dictate what laws get defended or the strength of that defense,” Brown wrote, adding that I-638 must be defended vigorously.

At the same time, Brown said his office “will not and cannot abandon” efforts to protect healthcare access and equal treatment for transgender people. “While voters have passed a law changing our state’s approach to school sports, many other laws remain on the books that protect the rights of transgender people in a wide range of contexts,” he wrote.

Brown described the appointment of outside counsel as “a common step we take when our office cannot handle a case ourselves,” citing potential conflicts of interest, a need for special expertise or workload. He called Bryan Cave Leighton Paisner a well-respected national firm with a substantial Washington presence.

“I am confident that this approach will best ensure that I-638 is appropriately defended in a way that its supporters can have confidence in, while also allowing our office to continue our other important work defending transgender rights,” Brown wrote. “My highest obligation is to Washingtonians, and I am confident that this approach best respects their will.”

The lawsuit argues that I-638 discriminates against all girls and infringes on their privacy by requiring them to verify their sex before playing girls school sports, without imposing the same requirement on boys sports. It also contends the initiative discriminates against transgender girls by excluding them from girls sports.

Let’s Go Washington, the political action committee that advanced I-638, has rejected the lawsuit’s discrimination and privacy allegations, saying most voters agree “that girls should have their sports and spaces protected.”

The case is being heard in King County Superior Court, where a judge could decide whether to halt the initiative before it takes effect next month.