CRANSTON — It has been nearly 20 years since judges confined William Sarmento and John A. Sarro to a state mental hospital here.

But until yesterday, the men, both found not guilty of murder by reason of insanity, retained at least one vital link to the outside world: the right to vote.

Last night, the Cranston Board of Canvassers severed that tie, declaring the pair too mentally impaired to cast ballots.

“The Constitution of the State of Rhode Island just doesn’t allow these people to vote,” said Joseph A. DeLorenzo, Jr., chairman of the board, after the unanimous ruling.

Lawyers for the Rhode Island Disability Law Center, who have represented Sarro and Sarmento in the matter, vowed to appeal the decision to the Rhode Island Board of Elections.

“It’s very disappointing,” said Kate Bowden, a staff attorney for the center.

The tense hearing spoke to the local passions elicited by the case.

Sarmento, after all, admitted to murdering two children in a widely publicized case. And DeLorenzo, a colorful, bare-knuckled veteran of Rhode Island politics, has made little secret of his disdain for the men.

But the tussle also underscores a broader, national debate over mental illness and voting.

In Missouri, advocates and state officials are squaring off in court over alleged restrictions on voting by the mentally ill.

In New Jersey, voters will decide in November whether to remove old language in the state Constitution that declares “no idiot or insane person shall enjoy the right of suffrage.”

And the American Bar Association recently urged federal, state, local and territorial governments to tread carefully in restricting the rights of the mentally ill to vote.

The back-and-forth has hardly produced a consensus.

The law on mental capacity and voting varies widely from state to state, according to Jennifer Mathis, deputy legal director for the Judge David L. Bazelon Center for Mental Health Law in Washington.

Nine states, including New Jersey, still bar “idiots” or the “insane” from voting, she said. Seven states impose no restrictions. And the rest fall somewhere in between.

But Paul S. Appelbaum, a professor of psychiatry at Columbia University, said that policymakers and the courts seem to be moving away from broad-brush bans on voting and toward a more careful, case-by-case approach.

“The trend in the last two decades has been to recognize that merely because someone is mentally ill, merely because they have been hospitalized, merely the fact that they have been placed under guardianship, does not necessarily mean that they are incompetent to vote,” he said.

That notion is at the heart of the case built by advocates for Sarmento, 40, and Sarro, 52.

Sarmento, who spent months living in sewers and abandoned houses as a teenager and was tortured by visions of Satan, admitted to murdering two boys, Frankie Lee Barnes, Jr., 9, and Jason Wolf, 6, in 1987.

Sarro wound up at Eleanor Slater Hospital after slashing a man’s throat in a bar in 1981. And shortly after confinement, he killed a fellow patient.

City voting records show the two have voted since their early days at the hospital.

But in October, Edward Desautel, a candidate for the state legislature, wrote a letter to the Board of Canvassers objecting to “the inclusion of these two incompetent murderers in our election” and requesting that the panel hold a hearing on their eligibility to vote.

The proceedings stalled when the Rhode Island affiliate of the American Civil Liberties Union raised concerns about Desautel’s filing.

But in June, Desautel again requested that the Board of Canvassers take up the matter. And earlier this month, the panel found there was reasonable cause to hold a hearing and vote, setting the stage for the meeting last night.

The dispute turned on a provision of the Rhode Island Constitution which holds that “no person who has been lawfully adjudicated to be non compos mentis shall be permitted to vote.”

The board found that Sarmento and Sarro had, indeed, been found non compos mentis, Latin for “not master of one’s mind,” when they were declared not guilty by reason of insanity.

And because twice-annual evaluations by the courts have not resulted in the men’s release, the panel found, the insanity finding stands.

Bowden, the attorney with the Disability Law Center, disputed that interpretation.

A finding of not guilty by reason of insanity refers to a specific moment in time, she argued, and says nothing about a person’s ability to understand campaign issues and vote years later.

And the law surrounding the twice-annual reviews focuses on whether an unsupervised presence in the community would create a likelihood of harm, she said, not the ability to choose between candidates.

But DeLorenzo dismissed those arguments as so much legalese.

“The problem is, everybody wants to be politically correct,” he said. “And they want to go out there and use technicalities to get around the law.”

The case, he insisted, is not about denying the mentally ill the right to vote, but about upholding the state Constitution.

But Bob Carolla, a spokesman for the National Alliance on Mental Illness, suggested the panel is simply out of step with the latest thinking on the place of the mentally ill in a democracy.

“I think it’s an aberration,” he said, of the case, “because frankly it looks backward rather than forward.”

dscharfe@projo.com