If a person lets something happens that he or she can prevent, without taking any action to prevent it, he or she will be taken by the law as having committed that action.
He seems to do, who does not oppose what he can oppose.
Rapalje and Lawrence define the term as:
"He who does not prevent what he can prevent, seems to commit the thing."
Similarly, this definition by Burrill:
"He who does not prevent a thing which he can prevent, is considered as doing it."
The Latin maxim is taken from Roman law.
REFERENCES:
- Burrill, A., A Law Dictionary and Glossary (New York: Voorhies Publishers, 1851), page 368.
- Rapalje, S.,and Lawrence, R., A Dictionary of American and English Law with Definitions of the Technical Terms of the Canon and Civil Laws (Jersey City: Frederick C. Linn & Co, 1888), page 1053.