I dissent from part II of the majority opinion. The majority, in apparent fervor to expand the scope of aider and abettor liability, revise by judicial decree the centuries-old definition of the crime of burglary. Such innovation is warranted neither by statute nor precedent. The conclusion that an aider and abettor to a burglary must form his burglarious intent prior to the perpetrator’s entry is a corollary of the axiomatic principle that the perpetrator of a burglary must possess the requisite pre-entry intent.
Current CALJIC No. 14.54, which provides that one convicted of aiding and abetting a burglary “must have formed the intent to encourage or facilitate the perpetrator prior to the time [that person] [] made the entry into the [structure] with the required specific intent” therefore correctly states the law, and the majority are wrong to discard it.
Nonetheless, I join the majority in affirming defendant’s conviction because I agree that the trial court had no sua sponte duty to give a CALJIC No. 14.54 instruction in this case.
I.
“Every person who enters any house [or other defined structure] . . . with the intent to commit grand or petit larceny or any felony is guilty of burglary.” (Pen. Code, § 459.) As this court declared more than 100 years ago, the crime of burglary is complete once a perpetrator has entered a structure with felonious or larcenous intent. “The . . . entry and the intent being found or given, the crime would be complete even though it should turn out that, contrary to the calculations of the burglar, the building was empty. The sting of the crime is, in short, the guilty purpose, without reference to the possibility of accomplishing it . . . .” (People v. Shaber (1867) 32 Cal. 36, 38.) The principle that burglary is complete after entry with intent to commit a felony or theft is still the law in California. (People *1052v. Brady (1987) 190 Cal.App.3d 124, 133 [235 Cal.Rptr. 248]; People v. Clifton (1957) 148 Cal.App.2d 276, 279 [306 P.2d 545].) Conversely, as we stated in People v. Hill (1967) 67 Cal.2d 105, 119 [60 Cal.Rptr. 234, 429 P.2d 586], a “burglary cannot be committed unless . . . specific intent exists at the time of entry and ... the jury should be so instructed . . . .” From this it follows that even when someone “breaks into the dwelling house of another . . . , but without burglarious intent, [he] is not guilty of burglary even if he actually commits a felony while therein.” (Perkins & Boyce, Criminal Law (3d ed. 1982) p. 933.)
To state that the crime of burglary is finished at the point of entry is not to assert the counterintuitive proposition that criminal activity has ceased at that point, but merely to recognize that the burglary has terminated, and the felony or theft that motivates the burglar commences or continues. Although common usage might refer to a “burglary in progress” once the burglar has entered a dwelling, the statutory law considers the crime of entry with felonious or larcenous intent—i.e., the burglary—as distinct from the actual felony or larceny intended. Similarly, the law differentiates between the criminal who forms his felonious or larcenous intent before entry into a dwelling and the one who forms a postentry criminal intent, and for good reason: one who enters a dwelling with felonious or larcenous intent possesses a different culpability, and poses a different kind of threat to society, than the innocent entrant who subsequently conceives a criminal purpose.
An aider and abettor to a specific intent crime must share the specific intent of the perpetrator. (People v. Beeman (1984) 35 Cal.3d 547, 560 [199 Cal.Rptr. 60, 674 P.2d 1318].) “[A]n aider and abettor will ‘share’ the perpetrator’s specific intent when he or she knows the full extent of the perpetrator’s criminal purpose and gives aid or encouragement with the intent or purpose of facilitating the perpetrator’s commission of the crime.” {Ibid.) An aider and abettor to a burglary must therefore have a specific intent to assist the perpetrator in gaining unconsented entry into a dwelling or other defined structure to enable the perpetrator to commit larceny or a felony.
It follows from these elementary principles that one who did not intend to aid the perpetrator at the point of the perpetrator’s entry into the structure did not aid and abet a burglary, since that person did not have the requisite intent at the time the burglary occurred. Rather, one who forms the intent to assist the burglar’s larcenous or felonious activity after the burglar’s entry would be guilty of aiding and abetting that larceny or felony, but not the burglary. Like the similarly situated perpetrator accused of burglary, the aider and abettor innocent of assisting the burglar’s entry is guilty of a different kind of offense than one who assisted that entry with the requisite intent.
*1053The majority rely on People v. Cooper (1991) 53 Cal.3d 1158 [282 Cal.Rptr. 450, 811 P.2d 742] in their effort to redraw the traditional boundaries of the crime of burglary. Although I continue to disagree with this court’s decision in Cooper, it is nonetheless plainly distinguishable from the present case. Cooper involved a determination of the duration of the crime of robbery for aider and abettor purposes. This court decided that, since asportation of stolen goods is one of the statutory elements of robbery, a defendant who did not participate in taking possession of the victim’s property but did assist in the asportation of the property by driving the getaway car was guilty as an aider and abettor, rather than as an accessory after the fact. Cooper analyzed the duration of the crime in terms of the crime’s elements. (Id. at p. 1165.) The only controversy in Cooper was over the point at which the act of asportation ceased. The majority held that asportation was finished only after the robbers carried the loot to a temporary place of safety. (Ibid.) The dissent, on the other hand, argued that “only slight asportation is necessary to make the crime of robbery complete.” (Id. at p. 1174, dis. opn. of Kennard, J.) The Cooper majority’s analysis nonetheless proceeded from its assessment of the duration of the criminal acts that are the statutory elements of the crime in question.
In this case, the elements of a burglary are, as discussed above, entry into a house or other defined structure with intent to commit larceny or a felony. Unlike the case of asportation of stolen goods, in which the word “asportation” could be understood to mean an act occurring over a period of time, the duration of the “entry” element in a burglary is confined by definition to the fixed point at which entry occurs. Thus this case departs from Cooper in that its analysis of the duration of the crime for aider and abettor purposes is no longer tied to a determination of the length of time of the acts that constitute the elements of the crime; the majority assert instead that the crime somehow continues after performance of all the elements of the crime have ceased.
In order to arrive at their conclusion, the majority resort to a facile comparison to the crime of rape, drawn from a footnote in the Cooper opinion. “ ‘[T]he rape victim . . . would not agree that the crime was completed once the crime was initially committed (i.e., at the point of initial penetration)’, but rather would consider the offense not to have ended ‘until all of the acts that constitute the rape have ceased.' . . . ‘[T]he unknowing defendant who happens on the scene of a rape after the rape has been initially committed and aids the perpetrator in the continuing criminal acts’ reasonably would be found to have formed the intent to facilitate the rape during the commission of the rape.” (Maj. opn., ante, at pp. 1040-1041, quoting Cooper, supra, 53 Cal.3d at pp. 1164-1165, fn. 7.)
*1054Yet the duration of aider and abettor liability for rape and burglary are clearly different matters. The crime of rape consists of an act of sexual intercourse that is nonconsensual. (Pen. Code, § 261.) Although the act of penetration, however slight, is sufficient to complete the crime of tape (Pen. Code, § 263), it is evident that the crime of rape continues for as long as the unlawful sexual intercourse persists. It is sexual intercourse, not penetration, that is the essential act of a tape. The reference in section 263 to “any sexual penetration, however slight” is intended not to define the entirety of such intercourse, much less to fix the duration of the crime of rape, but merely to define what is minimally required to establish the act element of a rape.
Burglary, on the other hand, is defined in terms of entry. Nonconsensual entry with felonious or larcenous intent is not the minimuih one must perform for a burglary, it is the definition of burglary itself. Again, although there are act elements of the crimes of robbery and rape—asportation and sexual intercourse respectively—that may be performed over an extended period of time, leading to a disjunction between the “threshold of guilt-establishment” of the crime and the complete “commission” of the crime (People v. Cooper, supra, 53 Cal.3d at p. 1164), that is not the case with burglary. Because the act element of the burglary—entry into a dwelling— occurs at a fixed point in time, the point at which a burglar’s culpability for burglary is established is also, in most cases, the point at which all the acts that constitute the burglary are finished. After that point of entry, the burglary, according to the statutory definition, has been completed, although the felonious or larcenous activity underlying the burglar’s intentions may continue. One who forms the intent to assist after this entry may be found guilty of aiding and abetting this criminal activity; he may not be convicted of assisting a burglary already complete.
The majority also attempt to justify their holding by quoting our observation in People v. Gauze (1975) 15 Cal.3d 709, 715 [125 Cal.Rptr. 773, 542 P.2d 1365] that “ ‘[bjurglary laws are based primarily upon a recognition of the dangers to personal safety created by the usual burglary situation—the danger that the intruder will harm the occupants in attempting to perpetrate the intended crime or to escape and the danger that the occupants will in anger or panic react violently to the invasion, thereby inviting more violence. The laws are primarily designed, then, not to deter the trespass and the intended crime, which are prohibited by other laws, so much as to forestall the germination of a situation dangerous to personal safety.’ Section 459, in short, is aimed at the danger caused by the unauthorized entry itself.”
The majority conclude that this interest in personal safety defines the duration of the crime. “The appearance and assistance of an aider and *1055abettor, even if belated, contributes to and perpetrates the increased danger and risk. For example, an individual might learn of the perpetrator’s earlier entry with the requisite intent, form his own intent to facilitate that offense, and commence acting as a ‘lookout’ at the point of entry, on behalf of the perpetrator. The presence of the ‘lookout,’ by prolonging the perpetrator’s presence in the structure, may increase the chance of an encounter between the perpetrator and a returning occupant.” (Maj. opn., ante, at pp. 1043-1044.)
Yet Gauze’s insight that the law of burglary is primarily interested in protecting personal safety cannot be used to justify the expansion of the statutorily defined liability for burglary. Indeed, the conviction of burglary in Gauze was reversed by this court. If the crime of burglary is intended to punish the unlawful entrant with the requisite intent, or his assistant, the larceny or felony laws are intended to punish one who, being innocent of helping the unlawful entry, assists the burglar in completing his criminal designs. The prosecution of the aider and abettor for the assistance in the commission or attempted commission of the felony or larceny that almost invariably follows a burglary is sufficient to protect personal safety against such postentry assistance of a burglar’s criminal enterprise.
Finally, the majority misread our pronouncements on aider and abettor liability in People v. Croy (1985) 41 Cal.3d 1, 12, footnote 5 [221 Cal.Rptr. 592, 710 P.2d 392]. As we stated there: “Like the conspirator whose liability is predicated on acts other than and short of those constituting the elements of the charged offense, if the acts are undertaken with the intent that the actual perpetrator’s purpose be facilitated thereby, he is a principal and liable for the commission of the offense. Also like a conspirator, he is guilty not only of the offense he intended to facilitate or encourage, but also of any reasonably foreseeable offense committed by the person he aids and abets.” But it does not follow from this that one who forms his criminal intent after the crime of burglary is completed may be held, as it were, retroactively liable for crimes committed prior to the formation of that intent. Croy merely reiterates the principle that an aider and abettor, or conspirator, is liable for the reasonably foreseeable crimes that issue from their criminal designs, whether or not those criminal acts are the ones specifically intended. But it is well established that “[a] conspirator cannot be held liable for a substantive offense committed pursuant to the conspiracy if the offense was committed before he joined the conspiracy.” (People v. Marks (1988) 45 Cal.3d 1335, 1345 [248 Cal.Rptr. 874, 756 P.2d 260], italics in original.) Neither can an aider and abettor be held liable for crimes committed before he begins to assist the criminal activity with the required intent.
For all of the foregoing, I believe the majority err in concluding that an aider and abettor who forms a postentry intent to aid a burglar to carry out a *1056theft or felony is guilty of the burglary. Moreover, I believe that CALJIC No. 14.54 is an accurate statement of the law, and should be continued to be given where appropriate.
II.
While dissenting from the majority’s conclusion that the duration of a burglary lasts until the perpetrator’s departure from the structure, rather than entry, I would affirm the judgment because I agree that, in this case, the judge had no sua sponte duty to give CALJIC No. 14.54 or a similar instruction. Although the evidence in this case certainly could have been interpreted to lead the jury to the conclusion that the defendant formed his intent to assist the perpetrator’s criminal activity after the perpetrator had entered the structure, neither the prosecution nor the defense relied on such a theory, nor was that theory conspicuously implied from the evidence presented. Therefore, although it would have been proper for the trial court to have given the jury a CALJIC No. 14.54 instruction if so requested, the majority correctly conclude that the trial court was not obliged to uncover on its own theories that the evidence presented would not “strongly illuminate and place before [it].” (People v. Wade (1959) 53 Cal.2d 322 [1 Cal.Rptr. 683, 348 P.2d 116].) On that limited basis I concur in the majority’s judgment.