A Supreme Court ruling and its dissent this week cleanly illuminated one of the most contentious issues of the Baldacci administration’s Dirigo Health plan. And while the court sided with the state, it left no doubt about its dismay over the way the Dirigo law was written. The decision is warning to all lawmakers who would attempt health-care legislation.

The specific question before the court was whether the Dirigo Health board of directors and the Maine insurance superintendent acted reasonably in calculating the “aggregate measurable cost savings” that produced the payment that insurers and others would pay to expand health coverage for Mainers under Dirigo. The court affirmed that the board and the superintendent had acted properly, but that’s not the interesting part of the ruling.

The 5-1 majority opinion, written by Chief Justice Leigh Saufley, first notes that “the Dirigo Health program is a unique statutory creation. … It has no history in the common law” and then spends a long and necessary stretch worrying about the ambiguity of the statute ordering the calculation of the cost savings from Dirigo. The worry is this: Trying to figure out how much a specific program saved when dozens of other factors could have affected health-care costs is hard enough. But what is meant by savings “is not defined elsewhere in the statute” beyond a statement saying the savings shall be determined. “Nor is it defined or even discussed in the statutes encompassed in the original” Dirigo act.

One result of this ambiguity was that while the Dirigo board found $136.8 million in measurable health care savings in the first year of operation, the superintendent found only $43.7 million. In a dissenting opinion, Justice Donald Alexander wrote, “The fact that the Dirigo Health Board of Directors and the Superintendent of Insurance could arrive at such dramatically different figures for ‘aggregate measurable cost savings’ demonstrates the significant ambiguity of the term and the highly subjective, judgmental analysis it invites the Board and the Superintendent to use in determining the savings offset charge.”

Both entities acted reasonably given an inadequate statute, but supporters of Dirigo should consider this warning. The administration already hopes to move away from broader interpretations of the measurable savings and return to counting bad debt and charity care.

Absent the ability to craft law that will take into account comprehensive and specific areas of savings produced by Dirigo, that decision is understandable. But the attraction of identifying savings within the health system is that it could make coverage more widely available and more affordable for all. So far, as this ruling highlights, Maine’s statutory language has yet to match the soundness of this idea.