Seventeen years ago, the state Court of Appeals ruled that New York State has a constitutional obligation to ensure that public schools provide all students with a “sound basic education.” The resulting litigation took 11 more years to resolve, culminating in a 2006 decision affirming that an aid increase budgeted under then-Gov. George Pataki had met the court’s definition of “minimally adequate” funding for New York City schools.

This week, the Court of Appeals cleared the way for a new wave of litigation based on the precedent set by that case, which was brought by the advocacy group Campaign for Fiscal Equity, better known as CFE.

In a 6-1 decision, the court upheld the denial of the state’s motion to dismiss a lawsuit filed on behalf of 101 parents whose children attend public schools in 13 small cities across New York — includingseven districts in the Hudson Valley as well as the state capital, Albany.

Although the original school funding case dealt solely with New York City, Gov. Eliot Spitzer chose in 2007 to expand the CFE approach statewide. But his plan to increase school aid by $7 billion over four years was soon derailed by the recession.

The parents in the new case claim that the state’s school funding policies, including aid cuts in recent years, have created an “opportunity gap” in small-city schools that the court must now correct.

There’s no dispute that these schools are producing bad outcomes, reflected in low test scores and graduation rates. The problem, as dissenting Judge Susan Read pointed out, is that the parents “seek increased funding on the theory that more money necessarily equals better student outcomes.” But that isn’t necessarily true.

As it happens, just last week, the Census Bureau issued updated data on K-12 expenditures throughout the country, data that puts this case in a broader context.

New York’s average spending of $18,618 per pupil was the highest of any state’s — 75 percent above the national average as of 2009-10. Most of the small-city school districts involved in the new lawsuit were also big spenders by national standards. Eight ranked among the highest-spending 10 percent of school systems nationally — topped by Mount Vernon’s $20,781 per pupil, which is in the top 5 percent, according to the census data. Even the lowest-spending small-city district — Jamestown, in the westernmost corner of upstate New York — spent 29 percent more than the national average.

Of course, these figures by themselves don’t prove anything — but they hardly support the notion that the funding of New York’s small-city schools is “grossly inadequate,” as the lawsuit claims. Yet, thanks to the CFE precedent and this week’s ruling, the courts will once again be seriously considering the claim. And it may not be too difficult for plaintiffs to prove their case, since the court-approved method for determining the adequacy of education funding is based on averages for “successful schools” within New York — the ultimate high-spending feedback loop.

Some legal scholars doubt the Court of Appeals could actually force the legislature to spend more. Nonetheless, as David Schoenbrod of New York Law School observed while the original CFE case was pending, “the court’s opinion does make a difference — not because the court can enforce it, but because most people seem to think the court can enforce it.”

“In other words,” Schoenbrod added, “it is a political fact” — the kind that prompted Spitzer to rashly make a $7 billion promise the state couldn’t keep.

As Judge Read warned back in 2003, the Court of Appeals’ CFE rulings “will no doubt inspire a host of future litigants representing other communities and school districts throughout the state.”

Obviously, she was right.