The three-page "legal demand" asks Attorney General Bob Ferguson to investigate seven constitutional issues with the law approved by voters in November.
The coalition - led by the Washington Education Association, the League of Women Voters and El Centro del la Raza - says if the attorney general doesn't take action, they will file a lawsuit in state courts. Their issues range from the way the law would divert money from public schools to private non-profit organizations to a perceived violation of the requirement that the superintendent of public instruction should supervise everything related to public schools.
They question the way levy dollars could be converted to a new purpose without consulting voters if a regular public school is converted to a charter school, as is allowed under the new law.
The group, which includes the state's largest teachers' union, doesn't like a provision of the new law that restricts collective bargaining units of charter school employees to the school in which they work.
"The Charter School Act is an unconstitutional law that impedes the state's progress toward fully funding public education and places even greater pressure on school districts to fill this gap," their letter said.
The attorney general's office did not immediately reply to a phone call requesting comment.
Washington became the 42nd state to OK the independent public schools in November. Voters authorized the opening of up to 40 charter schools over five years. The new law sets up a Charter School Commission to authorize groups to open charter schools and puts the State Board of Education in charge of approving applications by local school districts that also want to authorize charter schools.