## Facts

- A minor plaintiff, a passenger in an automobile, was injured in a collision with the defendant railroad’s train at a grade crossing in Granite City, Illinois.
- The plaintiff sued the Illinois railroad in a Missouri court for negligence arising from the Illinois accident.
- At trial, the court instructed the jury that contributory negligence was an affirmative defense and that the defendant bore the burden to prove it.
- The plaintiff obtained a $7,000 verdict and judgment.
- On appeal, the defendant argued that Illinois law required the plaintiff to plead and prove she exercised ordinary care (freedom from contributory negligence), and that the Missouri instruction misallocated the burden of proof.
- The intermediate appellate court affirmed but transferred the case to the Missouri Supreme Court to resolve conflicting Missouri authority on whether Illinois’s “due care” requirement is substantive or procedural.

## Issues

1. In a Missouri forum adjudicating an Illinois tort, whether Illinois’s rule requiring the plaintiff to allege and prove ordinary care (absence of contributory negligence) is substantive and therefore controlling.
2. Whether the trial court erred by instructing the jury under Missouri’s rule placing the burden of proving contributory negligence on the defendant.

## Decision

- The Missouri Supreme Court held that Illinois’s requirement that a plaintiff plead and prove due care is substantive and an essential element of the Illinois cause of action.
- Because the collision occurred in Illinois, Illinois substantive law governed the allocation of the burden of proof on contributory negligence in the Missouri action.
- The jury instruction placing the burden on the defendant was erroneous under the governing Illinois rule.
- The judgment for the plaintiff was reversed and the case remanded for a new trial with the proper burden allocation.

## Legal Principles

- Substantive law defines rights and duties giving rise to a cause of action; procedural law concerns the machinery for conducting litigation.
- When a forum court adjudicates a transitory cause of action arising in another state, it must apply the other state’s substantive law as that state’s courts apply it.
- If the foreign state treats plaintiff’s due care (freedom from contributory negligence) as an element of the negligence claim, that requirement is substantive for conflicts purposes, even if the forum generally treats contributory negligence as an affirmative defense.
- A forum’s local rule or statute allocating burdens of proof yields where the foreign law makes a different allocation part of the plaintiff’s right to recover.

## Conclusion

Because Illinois made the plaintiff’s exercise of ordinary care an element of recovery, Missouri was required to apply that substantive rule in an Illinois-accident case; the trial court’s instruction shifting the burden to the defendant was reversible error, requiring a new trial.


O’Leary ex rel. O’Leary v. Illinois Terminal R.R. Co., 299 S.W.2d 873 (Mo. 1957)