Voluntary intoxication means that a person voluntarily decided to get intoxicated. For example, if a person goes into a bar and consumes enough alcohol to be intoxicated, that person can be said to be voluntarily intoxicated.
When it comes to criminal law, voluntary intoxication can be a defense to a crime. However, this defense is only available for certain crimes. Generally, there are two types of crimes; specific-intent crimes and general-intent crimes. The defense of voluntary intoxication is only a defense to specific-intent crimes.
A specific-intent crime requires that a person commit an act with the intent to bring about a certain result. A general-intent crimes only requires that the person intended to engage in a specific act.
An example of a specific-intent crime is when person breaks into a building with the intent to commit a felony while inside the building (burglary). This is a specific intent crime because the State must prove that the person entered the building with intent to commit a felony-level crime while inside the building. The State does not need to prove that a felony was actually committed while inside the building.
An example of a general-intent crime is when a person operates a motor vehicle while intoxicated. The act of operating the motor vehicle while being intoxicated is what is prohibited. The State does not need to prove that the person intended to be intoxicated while operating the motor vehicle.