The california penal code codifies burglary in PC 459. This section lays out the elements of the crime of burglary as “every person who enters any house, room, apartment... with the intent to commit grand or petit larceny or any felony is guilty of burglary.” Additionally, the statute also includes an exhaustive list of types of buildings, vehicles, and even boats that count as a structure for the purposes of this statute.
Thus, PC 459 lists out the elements that must be proven by the prosecution. PC 459 indicates that the entry of the house must happen while the defendant has the “intent” to commit a felony. Therefore, it is not sufficient that a defendant merely broke into a house or a statutorily equivalent structure. Rather, there must have been intent at the time of entry to commit a felony. Thus, the prosecution has the burden of proving under PC 459 that the defendant entered a structure and that the defendant had the intent to commit a felony at the same time as the entry.
Therefore, if an individual's mental state were impaired at the time of entry - by means of alcohol, drugs, or the like - the defendant may have a strong defense based on a lack of mental intent. Furthermore, if an individual did not intend to commit a felony prior to entry, but only intended to commit a crime after he entered the structure, he will have a strong argument under PC 459 that his conduct did not constitute burglary because his entry was not contemporaneous with his intent to commit a felony.
Additionally, California differentiates degrees of burglary. The distinguishing factor is whether the burglary is committed upon a residence or a non-residence. When a burglary is committed upon a residence, it is classified as burglary in the 1st degree and counts as a strike, while burglary of a non-residence is classified as burglary in the second degree and is not a strike.