Attempt crimes are crimes where the defendant's actions have the form of the actual enaction of the crime itself, the actions must go beyond mere preparation.
The essence of the crime of attempt is that the defendant has failed to commit the actus reus (the Latin term for the "guilty act") of the full offense, but has the direct and specific intent to commit that full offense. The normal rule for establishing criminal liability is to prove an actus reus accompanied by a mens rea ("guilty mind") at the relevant time (see concurrence and strict liability offenses as the exception to the rule).
In English law, the test of proximity was:
In New York law, the element of actus reus is that person "engages in conduct which tends to effect the commission of such crime. The test this requires either:
Under the Model Penal Code, for a defendant to be convicted of attempt requires that he or she perform a "substantial step in a course of conduct planned to culminate in [the defendant']s commission of the crime" (MPC 5.01(1)(c)).
Under English law, s1(2) Criminal Attempts Act 1981 applies the Act even though the facts are such that the commission of the offense is impossible so long as, under s1(3), the defendant believes that he is about to break the law and intends to commit the relevant full offense. This reverses the House of Lords' decision in Haughton v Smith which had held it to be a good defense if the intended crime was factually or legally incapable of fulfillment. This change in the law avoids any problem in an early arrest because, once in police custody, it is impossible to commit the full offense. Further, both the incompetent criminal who fails because the means adopted are inadequate (e.g. intends to poison a victim but the amount administered is harmless, or makes a false statement that does not deceive the intended victim) and the unlucky thief who find the pocket or purse empty, can now be convicted.
Recklessness is not a sufficient mens rea. That means that the defendant must have decided to bring about, so far as lay within his or her powers, the commission of the full offense. However, transferred intent applies so that if "A" intends to murder "B" with a gun, but the shot accidentally misses and kills "C", then "A" is guilty of the murder of "C" and the attempted murder of "B". Alternatively, if "A" intends merely to frighten "B", and that same shot intentionally misses "B" but accidentally kills "C", "A" may be guilty of assaulting "B" (among other things), but not attempted murder, unless "A" intended that such fright would kill "B". Whether A would be guilty of murdering "C" would depend on the specific circumstances and what "A" foresaw. The punishment for an attempt is often tied to that of the intended offense (e.g., half the fine, or half the prison time).
Under English law, R v Walker and Hayles (1990) 90 Cr. App. R. 226 deals with the issue of the power of a court to impute intention based on foresight. The defendants threw their victim from a third floor balcony and were charged with attempted murder. The judge directed the jury that they could infer intention if there was a high degree of probability that the victim would be killed and if the defendants knew "quite well that in doing that there was a high degree of probability" that the victim would be killed. The Court of Appeal did not accept that the reference to "very high degree of probability" was a misdirection, but Lloyd LJ. stated that in the rare cases where an expanded direction is required to include foresight, courts should use virtual certainty as the test, rather than high probability (see also R v Woollin  3 WLR 382 (HL)). Also note that sometimes even mere intention to commit at an indeterminate time in the future may be criminalize, see grooming a child.
Recklessness will sometimes suffice for 'circumstances' of the crime. To be liable for attempted rape a defendant need not actually intend to have non-consensual intercourse, mere recklessness towards the lack of consent is enough (R v Khan). Likewise with attempted aggravated arson, recklessness towards loss of life will suffice (A-G's Reference #3 1992).
The "purpose" (as in situation 1) or "belief" (as in situation 2) required for an attempt do not necessarily encompass the attendant circumstances of the crime. Instead, the defendant must possess as to the attendant circumstances the degree of culpability required to commit the target offense, as specified in the elements of that offense.
However, many jurisdictions do not recognize abandonment. Courts that do recognize this defense generally apply it only where the defendant has completely and voluntarily renounces his or her criminal purpose (Understanding Criminal Law, J. Dressler, 2006). However, the abandonment is not complete and voluntary where the defendant desists from his or her criminal efforts due to unexpected resistance (e.g. from victims), the discovery of the absence of an instrumentality needed for the completion of the offense, or other circumstances that increase the probability of arrest, or decrease the probability of successful completion of the crime (e.g. proximate arrival of police). Abandonment is also invalid where the defendant simply postpones the criminal plan until another time.
Under the Model Penal Code, the defendant is not guilty of an attempt if he or she (1) abandons his or her effort to commit the crime, or prevents the crime from being committed, and (2) his or her behavior manifests a complete and voluntary renunciation of the criminal purpose (MPC § 5.01(4)). However, if renunciation is motivated in whole or part by one of the following, it is not complete: