Impossibility Defense in Criminal Law

The impossibility defense can only be applied for incomplete offenses (i.e. attempt). There are two types of impossibility defenses: factual impossibility and legal impossibility.

  1. Factual Impossibility – the defendant could not complete the crime because…; this defense seeks to negate the actus reus. The defendant is arguing that something got in the way of his completion of the crime. Generally, a factual impossibility defense is not permitted.
  2. Legal Impossibility – even if the defendant’s conduct was or is completed, it is not illegal.  Here, the court looks at the elements of the offense and finds that not all of the elements are present. Even if the defendant thought his conduct was wrong, a legal impossibility defense will be valid.

    Example: Defendant burns down his own house in order to collect the insurance proceeds. Under common law, arson required the burning of the dwelling of another. Therefore, it is legally impossible to find the defendant guilty of arson.


Conspiracy is the concerted effort or act of committing the crime. Conspiracy is a specific intent crime and the common law requires two parties for a conspiracy charge. Both parties must have the same mens rea or “mutuality” (See State v. Hayes). The common law does not require an over act or a step beyond preparation for the crime; however, it does require a showing of when the agreement (or implied agreement) was actually formed.

Under conspiracy, a defendant can be held accountable for acts that exceed the defendant’s initial agreement. In Pinkerton v. United States, the court held the defendant liable for acts of co-conspirators that occurred “in the furtherance” of the conspiracy. Under this standard, the court looks from the point of view of the conspiracy and states that those acts which are “reasonably foreseeable consequences of the conspiratorial agreement.”

Note: This standard is different from the natural and probable consequences doctrine under felony-murder which viewed forseeability from the perspective of the defendant.

Defeat the purpose of the conspiracy

Under the common law, a defendant could not abandon the original conspiracy. Once the defendant entered the conspiracy, he was stuck. However, the common law did allow a defendant to withdraw from the reasonably foreseeable consequences (aka the Pinkerton crimes). In order to withdraw from these consequences, the defendant had to notify the co-conspirators of his withdrawal and the withdrawal had to be completed within a reasonable amount of time so that the co-conspirators could also withdraw before the commission of the crime.

MPC Conspiracy

Under the MPC Section 5.03, both parties do not need the same mens rea (no mutuality required). Because conspiracy is a specific intent crime, the defendant can only be charged with conspiracy, attempt, or solicitation. The state must choose one of the three.

Under the MPC Section 5.03(6), renunciation must be presented as an affirmative defense if the defendant “thwarted the success of the conspiracy.” This could include calling law enforcement with a reasonable amount of time so that the co-conspirators could also withdraw. The MPC essentially rejects Pinkerton because it allows the defendant to avoid the conspiracy charge as a whole instead of only avoiding the foreseeable consequences with an appropriate renunciation.


List of Specific Intent Crimes


Common Law Solicitation

Solicitation is a general intent crime under the Common Law; however, it was typically treated as though it was a specific intent crime because solicitation is an incomplete crime like attempt. The defendant only needed to have a general intent that his conduct/solicitation will lead to the result of the crime; however, the defendant needed to “have the purpose” or specific intent that the third party will commit the crime.

Under common law, whenever the defendant completed the actus of asking a third party to commit a crime, the solicitation was complete. The law required that the state must show the defendant encouraged or induced through the statement (i.e. the defendant offers the third party tangible property if the third party commits a crime). In order to be found guilty, the defendant’s statement would have to indicate a clear mens rea that the third party commit the crime. Common law only looked at the statement by the defendant and not any actions surrounding the statement. No overt act required under Common Law or MPC. The statement was evaluated under an objective reasonableness standard.

Modern Solicitation

Modern statutes define solicitation as a specific intent crime.  For example, MPC Section 5.02 defines solicitation as:

“A person is guilty of solicitation to commit a crime if with the purpose of promoting or facilitating its commission [specific intent] he commands, encourages or requests another person to engage in specific conduct which would constitute such crime or an attempt to commit such crime or which would establish his complicity in its commission or attempted commission.”

If the defendant wants to end or renunciate the solicitation he must persuade the third party not to do the crime or otherwise prevent the commission of the crime. In order to renunciate from the solicitation, the defendant must manifest a “complete and voluntary renunciation of his criminal purpose” (Section 5.02(3)). Renunciation is presented by the defendant as an affirmative defense.


Helpful: General Intent Crimes List


Attempt is an “incomplete crime.” To constitute attempt, the defendant’s mens rea must have intended the actual conduct AND the actual result (or ultimate harm). In other words, attempt is a specific intent crime even if the attempted crime only requires general intent.

Common Law Attempt

The Common Law had four tests to determine whether the defendant attempted a crime:

1. Equivocality

Looked at the factual circumstances the defendant committed to show that it was unambiguous that the defendant intended the completed offense

2. Proximity

Under this analysis, the court balances the following tests:

(a) “Nearness” test. This test looks to see how close the defendant came to actually committing the offense.

(i) How many steps did the defendant take?

(ii) How many steps where left?

(b) Harm test. Looks at the ultimate result of the actual harm.

(i) How serious would the harm have been if the defendant committed the act?
The less serious the harm, the closer we need in “nearness;” the more serious the harm, we don’t need to get as close in “nearness”

(ii) What would it take to prevent the harm? The more police involvement required (government intrusion), the further we can be away from the nearness

3. Desistance

  1. Looked at the events as a causation; (another type of proximity test);
  2. From our causation link, is there a point in time when a reasonable person would/could have stepped in and stopped him?
  3. The goal of the desistance test is to determine the point in time when a reasonable person could have stepped in and stopped the offense (reasonable person analysis)
  • Reasonable person – someone of common intelligence who wants to avoid serious bodily injury to himself
    • If they could step in, they would.
    • Analyze seriousness of the harm to determine if the reasonable person would step in
    • The last point in time that a reasonable person would have stepped in is the point of desistance

4. Last Act

The last act before a defendant can change is mind before completing the offense of attempt.

MPC Attempt

The MPC Section 5.01 only has one test: “substantial step.” However, 5.01(2) specifically lists conduct which may be held as a substantial step. The MPC does require that a defendant’s conduct be strongly corroborative of his criminal purpose in order to constitute a substantial step. Examples, from section 5.01(2), of what may constitute a substantial step include:

  • lying in wait, searching for or following the contemplated victim of the crime
  • possession of materials to be employed in the commission of the crime, which are specifically designed for such unlawful use or which can serve no lawful purpose of the actor under the circumstances
  • soliciting an innocent agent to engage in conduct constituting an element of the crime

For Defenses to Attempt see Impossibility

More Helpful Information: List of Specific Intent Crimes


Murder under Common Law was the “the killing of another with malice aforethought.” Malice means the defendant had a malignant heart with the intent to kill; a heart devoid of social duty and fatally bent on mischief. A defendant could be charged with implied malice murder (which is not a separate crime; still murder) if he acted with a malignant heart and the defendant knew there was a high risk of death or grievous bodily injury.

Under modern law, many states have subdivided murder into degrees. For example, first-degree murder is the premeditated killing of another. In second-degree murder, the defendant still has malice but no premeditation. Premeditated has been interpreted to mean planned, deliberate, and willful. How much time is required for premeditation? Courts have differed. (Compare Commonwealth v. Carroll holding that no time is too short for the necessary premeditation to occur; the space of time between the premeditation and the fatal act is immaterial if the killing was in fact intentional, willful, and deliberate; against State v. Guthrie stating that “to allow the State to prove premeditation…by only showing that the intention came into existence for the first time at the time of such killing completely eliminates the distinction between the two degrees of murder;” there must be some appreciable amount of time.)

Some things courts will weigh (although these are not usually given the same weight):

  1. Person of ordinary judgment would know it is reasonably certain to cause serious bodily injury
  2. Done from some ill will/hatred
  3. Indicates indifference/depraved indifference to life

The MPC Section 210.2 states that “criminal homicide constitutes murder when:

(a) it is committed purposely or knowingly; or

(b) it is committed recklessly under circumstances manifesting extreme indifference to the value of human life.”

In section (a), the MPC ask was the murder purposeful or did the defendant do it knowingly? If yes, the defendant is guilty of murder.

In section (b), the MPC asks whether the defendant exhibited extreme indifference to the value of human life. For the defendant to manifest extreme indifference, he must have some conscience awareness.

Section (b) also notes that “recklessness and indifference are presumed if the actor is engaged or is an accomplice to” a felony (whether in the commission of, while attempting to commit, or in flight after committing/attempting). This is essentially the common law felony-murder rule.


Felony-Murder is charged to a defendant when a homicide occurs as the defendant is committing or attempting a felony. A felony-murder charge can only be brought if (1) the underlying felony is inherently dangerous, (2) the felony and murder are two separate offenses in order to avoid merger, and (3) the defendant’s felony has a casual link to the murder.

1. Inherently dangerous

Most common law crimes can be considered inherently dangerous. Examples of inherently dangerous felonies are arson, burglary, kidnapping, and rape. However, if a crime has not been labeled inherently dangerous either through common law or the legislture, courts turn to two different tests to determine whether the underlying felony was inherently dangerous:

(a) In abstract

Under this test, a court asks whether a situation could exist where serious bodily injury or death would not have been foreseeable when the defendant committed the felony. This test focuses on the mens rea and was applied in People v. Phillips; however, it is followed by a minority of jurisdictions.

(b) As perpetrated

Under this test, a court looks at the commission of the felony in the particular circumstances and asks, “was the felon careful enough to avoid an inherently dangerous felony?” This test focuses on the actus reus. Most jurisdictions use this test.

2. Merger

The felony and murder must be two separate offenses otherwise the felony “merges” with the murder and the defendant cannot be charged with felony-murder. This question is really one of statutory construction.

To ensure that the felony and murder are two separate offenses, a court first does an “included in fact analysis.” Two separate offenses do not exist if all of the evidence that will be presented, by the state, in order to prove the felony is the same evidence that is needed in order to prove the homicide. Specifically, the evidence required to prove the “integral” elements of the two offenses.

A court will also look to ensure that an independent felonious purpose exists (See People v. Burton). This means that the felony must have a purpose other than serious bodily injury or death (because the purpose of murder is serious bodily injury or death). This is a legal conclusion which is not determined from the perpetrators perspective. If an independent felonious purpose exists then you cannot merge because we must have two separate offenses and the defendant can be charged with felony-murder.

3. Causation

Two different analysis have been propagated by courts to determine if the felony the defendant committed had a casual link to the homicide.

(a) Proximate cause analysis

This analysis limited the application of felony-murder to the natural and probable consequences of the underlying felony; in other words the foreseeable consequences of the felony. Under this analysis, the court will make a factual inquiry and look at the specific conduct the defendant committed. The defendant’s felony must be a sufficiently direct cause of the homicide. (See Warner-Lambert). This proximate cause analysis was done under the old common law and is only still used by a minority of jurisdictions.

(b) “In the furtherance of

This is a different type of causation analysis where the court looks at a joint plan or underlying felony from a general intent perspective instead of the conduct (a specific intent perspective). The court asks whether or not the death was in furtherance of the joint plan or underlying felony. If the defendant was not the direct cause, he must be a member of a joint group that commits the underlying cause. The “in furtherance” test is the modern analysis and now used by a majority of jurisdictions.

Again, a felony-murder charge can only be brought if (1) the underlying felony is inherently dangerous, (2) the felony and murder are two separate offenses in order to avoid merger, and (3) the defendant’s felony has a casual link to the murder.


Under the United State Common Law, rape has four main elements:

  1. Sexual intercourse (includes some penetration no matter how slight)
  2. With a woman not his wife
  3. Using physical force
  4. Without her consent*

*The victim must give consent at the time the mens rea and actus reus come together. Consent must be freely and voluntarily given, express and unequivocal. In most cases, consent will be an affirmative defense.

MPC Section 213.1, “a male who has sexual intercourse with a female not his wife is guilty of rape if:

(a) he compels her to submit by force or by threat** of imminent death, serious bodily injury, extreme pain or kidnapping, to be inflicted on anyone; or

(b) he has substantially impaired her power to appraise or control her conduct by administering or employing without her knowledge drugs, intoxicants or other means for the purpose of preventing resistance; or

(c) the female is unconscious; or

(d) the female is less than 10 years old.”

**The “force or threat” requirement has been applied differently throughout the country. In some jurisdictions, penetration is serious bodily injury and is enough to show force (See State in the Interest of MTS holding that the physical force requirement acts only to “qualify the nature and character of the sexual penetration.”) Other jurisdictions require that the threat of force involve death or serious bodily injury. (See People v. Evans holding defendant not guilty because no finding of forcible compulsion or threat beyond a reasonable doubt.)

Intervening Causes in Criminal Law

An intervening cause occurs when there is some interruption between the defendant’s conduct and the ultimate harm or result. See People v. Acosta for a great example.

Here is how to conduct an analysis to determine if a defendant is still liable in the presence of one or more intervening causes:

First, is the intervening cause dependent or independent on the defendant’s conduct? For example, the intervening cause is dependent if it would not have occurred without the defendant’s conduct (e.g. a security guard firing a pistol because the defendant is robbing a bank).

  • If the intervening cause is dependent on the defendant’s conduct, was it foreseeable or unforeseeable?
    • If the intervening cause was foreseeable and dependent then a court can hold the defendant liable if the result was intended or reasonably foreseeable
    • If the intervening cause was unforeseeable (or not a strong foreseeable link) but dependent then a court can hold the defendant liable if the result was sufficiently related to the actor’s conduct to impose liability (or, in the converse, it would not be fair to hold the defendant liable)
  • If the intervening cause is independent of the defendant’s conduct, then the intervening cause was not reasonably foreseeable and there is no sufficient relationship to the defendant’s conduct. Therefore, it is unfair to hold the defendant liable for the result of the intervening cause.
    • This is known as an independent superceding cause

Causation in Criminal Law

Crimes such as homicide, where the result of the defendant’s conduct is a necessary aspect of the crime, may require a causation analysis. The causation analysis will require that the defendant’s conduct be the actual cause and proximate cause in order to find the defendant liable. (See Warner-Lambert holding that the court must find a causal link first before determining whether defendant acted at reckless.)

The defendant’s conduct is the actual cause if “but for” the defendant’s conduct, the result would not have occurred. In order to find proximate cause: (1) the defendant’s conduct must be closely connected to the result, (2) the defendant’s conduct has a significant connection to the result, and (3) the law is justified in imposing liability.

The MPC Section 2.03 states that “conduct is the cause of a result when:

a. It is an antecedent but for which the result in question would not have occurred; and
b. The relationship between the conduct and result satisfies any additional causal requirements imposed by the Code or by the law defining the offense.”

The MPC looks at the cause in fact and then the mens rea. In other words, a court should ask “What was the mens rea towards the actual result?” The MPC does not talk about causation in terms of foreseeability but in terms of remoteness. If the result was too remote or too accidental [MPC Section 2.03(2)(b)], the defendant will not be held liable (looks backwards).

General Intent vs. Specific Intent

Intent crime

The difference between general intent and specific intent:

  • General intent – the defendant intended the conduct
  • Specific intent – the defendant intended the conduct and the result

For a specific intent crime, the mens rea will typically be written into the statute. Intentional and knowledge based crimes are considered specific intent crimes. Here is a (not exhaustive) list of specific intent crimes:

  1. Murder
  2. Attempt
  3. Conspiracy
  4. Solicitation (under modern statutes)
  5. Larceny
  6. False Imprisonment

Note: A specific intent crime cannot merge.

General intent crimes typically include crimes that are based on the defendant being reckless or negligence. Here is a (non exhaustive) list of general intent crimes:

  1. Manslaughter
  2. Negligent Homicide
  3. Solicitation (however, it is treated like a specific intent crime and modern statutes define it as a specific intent crime)
  4. Arson
  5. Rape