If one party is more than half at fault, what is this defense against negligence called?

The correct answer is comparative negligence. This legal principle comes into play when assessing the degree of fault of each party involved in a negligence claim. Under comparative negligence, if one party is found to be more than 50% at fault for the incident, they may not be able to recover damages from the other party. Instead, their compensation could be reduced based on their own percentage of fault.

This approach allows for a more equitable allocation of responsibility and can provide a mechanism for determining damages based on the degree of each party's negligence. It contrasts with other legal concepts such as negligence per se, which deals with violations of statutes, or strict liability, which assigns liability without fault. Additionally, vicarious liability is a different concept where an employer may be held responsible for the negligent actions of an employee conducted within the scope of employment, rather than focusing solely on the fault of the parties involved in a specific incident.