The 85-page opinion said, however, that the judiciary would keep an eye on lawmakers to make sure they fully implement education reforms by 2018.
"The court cannot idly stand by as the legislature makes unfulfilled promises for reform," Justice Debra Stephens wrote in the majority opinion. She notes that deadlines for reforms keep getting moved back and if left up to the Legislature, the court expects the delays would continue.
Lawmakers, who convene next week for a 60-day session, will also need to focus on what to do about a nearly billion dollar budget shortfall.
A coalition of school districts, parents, teachers and community groups won a lawsuit in King County Superior Court in February 2010. Judge John Erlick ruled the state was violating its constitution by not fully paying for basic education.
The state appealed, saying Erlick reached beyond the high court's previous ruling on this issue in 1978.
The Supreme Court held a lively public hearing on the case at the end of June. Many of their questions concerned whether the Legislature had made any progress lately in improving the way the state pays for education.
In the strongly worded conclusion of the ruling issued Thursday, the court outlines the ways the Legislature has failed to meet its obligations - by talking about reform but cutting school funding at the same time.
The court does not lay out a plan for maintaining that oversight, and Stephens acknowledges that work won't be easy.
"While we recognize that the issue is complex and no option may prove wholly satisfactory, this is not a reason for the judiciary to throw up its hands and offer no remedy at all," she wrote.
In a partial dissent, Chief Justice Barbara Madsen disagreed with the majority on the issue of who should make sure the court's decision is carried out.
"We have done our job; now we must defer to the legislature for implementation," she wrote, noting the Supreme Court set a precedence of having the Legislature do this work when it ruled in a 1978 decision on a similar case.
"The means of compliance are firmly within the realm of legislative power," Madsen wrote. She said the majority claims that the judiciary will "facilitate progress" by maintaining authority over the case but then fails to say how it will do that.
House Speaker Frank Chopp said the priority this legislative session will be to maintain current funding for basic education and then take a look at what should be the next steps in education reform.
Senate Majority Leader Lisa Brown, D-Spokane, said there are valuable education programs outside of the basics that may still be in danger of losing state dollars, including levy equalization, which gives financial help to property-tax poor school districts.
"Simply protecting basic education does not mean there won't be some significant cuts," she said at a legislative forum on Thursday morning.
Brown said the Supreme Court could help out the Legislature by taking a closer look at the constitutionality of a citizen initiative that forces lawmakers to get a two-thirds vote on any tax or fee change.
Gov. Chris Gregoire said one of the next steps should be finding a more stable source of money for education in Washington state.
"This ruling reinforces my call for a half-penny sales tax increase to invest in education," she said in a statement, although the ruling does not mention the tax increase.
"If we don't, we take a step backward and not only threaten a violation of the court's ruling, but make it more difficult for students to gain the skills and knowledge needed to compete in today's global economy," the governor said.
Superintendent of Public Instruction Randy Dorn said the ruling reinforces what he's been saying for years, that education funding is not adequate and further cuts are out of the question.
Dorn thanked the court for issuing its ruling before the 2012 Legislature convened.
"The court understood that the issue of education funding is too important to Washington state to have waited until the end of another session," he said.