Who has the burden? The question at the center of the Lindsay Clancy case

A Plymouth County jury could not reach a verdict in the Lindsay Clancy case, and the trial ended in a mistrial on September 4, 2026. Nearly every account of the case described it as a fight over whether she was mentally ill. That was not really the question. The more important question was who had to prove what.

Where the burden falls

Massachusetts does not technically call this the insanity defense. It uses the term lack of criminal responsibility, and the distinction matters because of where the burden falls.

Under the Massachusetts rule, once the issue of criminal responsibility is properly raised and there is some evidence supporting it, the Commonwealth has to prove beyond a reasonable doubt that the defendant was criminally responsible at the time of the offense. The defendant does not have to prove that she was not criminally responsible. She has a burden of production to raise the issue, but the burden of persuasion remains with the Commonwealth.

The test comes from a 1967 decision, Commonwealth v. McHoul, which adopted the Model Penal Code formulation: a person is not criminally responsible if, as a result of mental disease or defect, she lacks substantial capacity either to appreciate the criminality or wrongfulness of her conduct or to conform her conduct to the requirements of the law. There are two separate routes, joined by or.

What that meant at trial

That explains the shape of the trial. If the burden is on the Commonwealth, the defense does not have to win the psychiatric argument. It has to give the jury enough evidence that it cannot determine, beyond a reasonable doubt, that the defendant was criminally responsible.

That distinction also explains what happened after the mistrial. On October 1, 2026, the trial judge denied the defense’s renewed motion for a required finding of not guilty, concluding that the evidence was sufficient for a rational jury to find the defendant criminally responsible beyond a reasonable doubt. The judge was not deciding which expert was right; that was a question for the jury.

A retrial has not been scheduled, and the Commonwealth has not announced whether it will seek one. Clancy’s motion to bar a retrial on double jeopardy grounds remains pending, with argument set for November 2, 2026.

The thing people get wrong

Treating a diagnosis as the answer to the burden question. Whether someone has a psychiatric condition is a medical question. Whether that condition meets a state’s legal test for criminal responsibility is a completely different question, decided by a jury applying a legal standard.

And the jury is not required to accept an expert’s opinion simply because the expert has credentials. Massachusetts law allows the jury to consider the defendant’s conduct and the circumstances surrounding the offense in deciding whether the Commonwealth has proved criminal responsibility. Expert testimony is important, but it does not decide the issue for the jury.

That is also why the Massachusetts Supreme Judicial Court’s 2016 decision in Commonwealth v. Lawson matters. The court rejected the old language of a “presumption of sanity,” explaining that it is not really a presumption at all, but an inference that a person is probably criminally responsible. Once the defendant offers evidence raising lack of criminal responsibility, that inference alone cannot carry the Commonwealth’s burden beyond a reasonable doubt.

How this works in Texas

Texas asks a different question of a different party.

Under section 8.01 of the Texas Penal Code, insanity is an affirmative defense if, at the time of the charged conduct, the actor, as a result of severe mental disease or defect, did not know that the conduct was wrong. Unlike Massachusetts, Texas places the burden of proving insanity on the defendant, by a preponderance of the evidence. Texas also does not have the same volitional “conform conduct” route found in the Massachusetts test.

The takeaway

Two states are looking at the same facts but are not necessarily asking the jury the same legal question, and they are not necessarily putting the burden on the same person. The useful question in a case like this is never simply whether the defendant was mentally ill. The useful questions are who has the burden, what exactly do they have to prove, and what standard applies.

Change any one of those, and the same psychiatric evidence can produce a very different legal result.