## Facts

- Bruce L. Johnson was charged with murder, kidnapping, and assault with intent to commit rape involving a 14-year-old girl.
- Johnson pleaded not guilty by reason of insanity.
- At trial, the jury was instructed under Rhode Island’s then-governing M’Naghten insanity standard.
- The jury rejected the insanity defense and convicted Johnson on all charges.
- Johnson appealed, asking the Rhode Island Supreme Court to reconsider the state’s insanity test and its application to his case.

## Issues

1. Whether Rhode Island should abandon the M’Naghten rule and adopt the Model Penal Code (MPC) test for criminal insanity.
2. If a new insanity test is adopted, whether Johnson is entitled to a new trial under the new standard.

## Decision

- The court abandoned the M’Naghten rule and adopted the MPC “substantial capacity” test for insanity.
- Under the MPC test, a defendant is not criminally responsible if, due to mental disease or defect, the defendant lacked substantial capacity either (a) to appreciate the criminality (wrongfulness) of the conduct or (b) to conform conduct to the requirements of law.
- The court reversed Johnson’s convictions and remanded for a new trial with jury instructions applying the MPC standard.

## Legal Principles

- Criminal responsibility presupposes culpability; insanity doctrine limits punishment where mental disease or defect defeats blameworthiness.
- The M’Naghten rule is inadequate where it focuses narrowly on cognitive knowledge of right and wrong and effectively requires near-total incapacity.
- A valid insanity standard should account for both cognitive impairment and impaired behavioral control while preserving the jury’s role as the final decisionmaker on criminal responsibility.
- The MPC test is satisfied by a lack of “substantial capacity,” not complete incapacity, to appreciate wrongfulness or to conform conduct to law.
- When a court changes the governing insanity standard to a materially broader test, fairness may require a new trial so the jury can apply the correct legal standard to the evidence.

## Conclusion

Rhode Island replaced the M’Naghten insanity rule with the MPC substantial-capacity test and granted the defendant a new trial because the prior jury verdict was reached under a narrower, superseded standard of criminal responsibility.


State v. Johnson, 399 A.2d 469 (R.I. 1979)