Proving a criminal or civil case normally requires proving the mental state of the defendant, specifically showing that the defendant intended to commit the act for which he or she is being prosecuted. State of mind usually plays an important part in criminal or civil responsibility; the element of intent is critical to prove liability. A killing cannot be “murder” without a showing of intent to kill. Fraud or misrepresentation cannot be proven unless there is a showing that the defendant intended to deceive the plaintiff. The mental state of the defendant is almost always a key ingredient to a showing of criminal or civil culpability.
In some cases, however, the defendant’s intent is irrelevant. “Strict liability” offenses exist regardless of the defendant’s intent.
In criminal law, traffic violations are prime examples of strict liability offenses. If you are caught driving under the influence of alcohol or drugs your mental state does not matter. “I didn’t intend to become intoxicated” is not a valid defense. Speeding violations are similar. If you travel at 80 miles per hour and are caught, you are guilty regardless of your reason or mental state. You can be entirely unaware of your speed (and thus have no intent to speed) and still be guilty.
In civil law, product liability is also a strict liability case. If a manufacturer puts a dangerous product into the stream of commerce (think defective airbags in an automobile) the product manufacturer will be found liable regardless of their mental state – even if they clearly intended to make a safe product. Another form of strict liability in the civil context involves hazardous activities. If you operate a quarry and conduct blasting activities, any damage you cause as a result of the blasting will be your responsibility regardless of your intent and regardless of how careful you attempted to be.
The reason intent is not a factor in strict liability offenses is because society has made a judgment that protecting the public at large in all cases outweighs any issue involving the defendant’s intent or state of mind. Essentially, society is saying that if you engage in certain conduct you must adhere to the letter of the law every time, without exception.
— Kevin Palmer