Right from the start, we knew that the effort to block construction of an electrical transmission line in western Maine was all about power. But it turns out not to be the kind of power we had in mind.

Ultimately, it was not an issue of whether a high-voltage line that brings hydroelectric power from Canada to Massachusetts via Maine is good for the environment, for utility customers, for Maine’s economy or for the corporations that would profit. The Maine Supreme Judicial Court ruled last week that it was a question of who has the power to balance those factors and reach a decision under our constitutional system.

The court ruled Thursday that the state Public Utilities Commission and the courts had the power to decide whether a project complies with the applicable  laws and regulations. After a lengthy process, the PUC made a decision that was upheld on appeal, and the justices said you can’t pass a law ordering them to reverse their decision – as the referendum backers sought to do.

For the first time ever, Maine’s highest court has blocked a referendum from going to the voters. While supporters of the ballot question are understandably disappointed that they won’t have a chance to make their case in a statewide campaign, they should, on some level, appreciate this decision. When we see a president in Washington use executive orders to subvert the will of Congress – and when, for partisan reasons, Congress lets him do it – we should all be aware of the need for limited power of the legislative, executive and judicial branches of government.

The Maine court’s decision barely mentioned the issues that led opponents of the New England Clean Energy Connect project, proposed by Central Maine Power, to gather signatures in order to get a question on the ballot.

Instead, the ruling focuses mostly on the limits of what you can do through lawmaking. The court quoted an earlier decision that described the characteristics of a legislative act, which include: That it makes a law rather than executes one; that the law is applicable generally and not just in one case; and that it does not involve a subject that the Legislature has delegated decision-making power to an agency like the PUC.

Had it passed, the referendum would have ordered the PUC to throw out not only its decision, but also the testimony of witnesses and staff experts the commissioners evaluated before making their final determination. Imagine if at the end of every regulatory process, the final decision were subject to an up-or-down vote by people who are not bound to apply any laws or even look at the details of what’s proposed. Imagine if jury verdicts were subject to a popular vote by people who didn’t watch the trial.

“What is proposed here is not legislation,” the court said. “Directing an agency to reach findings diametrically opposite to those it reached based on extensive adjudicatory hearings and a voluminous evidentiary record, affirmed on appeal, is not ‘making’ and ‘establishing’ a law.”

Legislative power can be used to set limits on future power projects or to change the way the state regulates private companies like CMP. It could even be used to eliminate private utilities and replace them with consumer-owned nonprofits, as has been proposed by state Rep. Seth Berry, D-Bowdoinham.

But legislation can’t be used to overrule a regulatory process if that process was fairly conducted. Some will see this as a loss, but it’s a much-needed win for the rule of law.