The dangerous proximity test is a common law standard that decides when a would-be criminal has moved past mere planning and can be convicted of a criminal attempt. Justice Oliver Wendell Holmes Jr. developed it in 1901, and it asks one question: did the defendant come so close to completing the crime that it probably would have happened if no one had interfered? Everything short of that line is preparation, which the law does not punish. Everything past it is attempt.
Where the Test Comes From
Holmes first laid out the doctrine in Commonwealth v. Peaslee, a Massachusetts arson case. The defendant had arranged flammable materials inside an insured building so they were ready to be lit, then drove toward the building with an employee before changing his mind a quarter mile away and turning back. Holmes wrote that when preparation “comes very near to the accomplishment of the act, the intent to complete it renders the crime so probable that the act will be a misdemeanor,” even though the defendant still needed one more exertion of will to finish the job. He added that the closeness required for an attempt can shift depending on how serious and how likely the intended crime is.1Justia Law. Commonwealth v. Peaslee
That sliding-scale idea became the heart of the doctrine. The more dangerous and probable the planned crime, the less close to completion a defendant needs to get before the law calls it an attempt.2H2O. Kreitzberg Criminal Law Casebook – Notes and Questions United States v. Mandujano
What the Test Actually Asks
The dangerous proximity test looks primarily at what still had to happen for the crime to succeed, not at what the defendant had already done. Courts applying it weigh a handful of related factors.
- How close the defendant was in space and time to completing the crime. Someone standing outside a bank vault with safecracking tools is in a very different position from someone who bought those tools last week and left them in a garage.
- How many steps still had to occur before the crime would be complete. Fewer remaining steps push the conduct toward attempt.
- How serious the planned offense was. Preparation for murder may qualify as an attempt at an earlier stage than preparation for petty theft, because the stakes of getting it wrong are higher.2H2O. Kreitzberg Criminal Law Casebook – Notes and Questions United States v. Mandujano
- Whether the crime would have been committed “in all reasonable probability” if no one had intervened. This is the overarching question that ties the other factors together.3Justia Law. People v. Rizzo
None of the factors works alone. A court weighs them together, and the gravity factor can pull the threshold closer to preparation when the intended crime is especially dangerous.
Preparation Versus Attempt: The Rizzo Line
The distinction between punishable attempt and unpunishable preparation is where the dangerous proximity test does its real work. Buying a weapon, scouting a location, drawing a map: these show intent, but standing alone they do not put anyone in immediate danger. The test asks whether the defendant crossed from planning into conduct so close to the finish line that the crime was practically inevitable.
People v. Rizzo (1927) is the textbook illustration. Charles Rizzo and three accomplices planned to rob a payroll courier named Rao. Two of the men carried firearms. They drove around New York City visiting a bank and several construction sites looking for Rao, but never found him. Police who had been following the group arrested all four after Rizzo ran into a building.3Justia Law. People v. Rizzo
The New York Court of Appeals reversed the robbery conviction. The defendants had never located their victim, no one carrying a payroll was at any of the places they stopped, and no money had been withdrawn from the bank at the time of arrest. The court put it plainly: “these defendants had planned to commit a crime and were looking around the city for an opportunity to commit it, but the opportunity fortunately never came.”3Justia Law. People v. Rizzo However determined they were, they had not come “dangerously near” to actually taking anyone’s property. Driving around armed and looking for a target was still preparation because too many steps remained.
Change the facts slightly. Suppose the same group finds Rao, approaches him on the sidewalk, and is tackled by police seconds before the robbery. There, the crime was about to happen. The only thing missing was the final physical act. That gap between “still searching” and “seconds away” is exactly what the test is designed to identify.
How It Compares to the Substantial Step Test
The dangerous proximity test is one of several standards courts have used to draw the preparation-attempt line, and it has largely been displaced in most American jurisdictions by the Model Penal Code’s substantial step test.
The MPC flips the question. Rather than asking how much is left to be done, it asks how much the defendant has already done. A person is guilty of attempt if they take a “substantial step” toward the crime, and that step strongly corroborates criminal intent.4Legal Information Institute. Attempt The MPC lists specific conduct that can qualify, including lying in wait, following the intended victim, enticing the victim to the planned location, scouting the location, unlawful entry into a building or vehicle connected to the crime, possessing specialized materials that serve no lawful purpose for the defendant, and soliciting an unwitting accomplice.5OpenCasebook. Model Penal Code (MPC) 5.01 Criminal Attempt
The practical difference is large. Under the MPC, the defendants in Rizzo could have been convicted: they were armed, they were searching for the victim, and their conduct strongly corroborated a plan to rob. Under dangerous proximity, they walked free because they never got close enough. The MPC lets law enforcement intervene much earlier in the planning process, which is the main reason most jurisdictions have shifted toward it.
Two older common law tests appear in the case law but are rarely used as standalone standards today. The equivocality test (sometimes called the res ipsa loquitur test) asks whether the defendant’s conduct at the moment they stopped clearly pointed to a criminal purpose with no other plausible explanation, ignoring what the defendant said or planned. The probable desistance test asks whether the defendant had passed the point where an ordinary person would have voluntarily turned back. Of the four tests, the dangerous proximity test is the most defendant-friendly; the substantial step test is the most prosecution-friendly.
What Happens When a Defendant Backs Out
The dangerous proximity test raises an obvious follow-up: what if a defendant gets close and then voluntarily quits, as the defendant in Peaslee did when he turned his carriage around a quarter mile from the building?1Justia Law. Commonwealth v. Peaslee Common law courts split on whether a genuine change of heart could undo attempt liability once conduct had crossed the line.
The Model Penal Code addressed this directly. Under MPC Section 5.01(4), a defendant has an affirmative defense if they abandoned the effort or prevented the crime under circumstances showing a “complete and voluntary renunciation” of criminal purpose. The renunciation has to be genuine. A defendant who stops because the risk of getting caught suddenly increased, or who simply postpones the crime for a better opportunity, does not qualify. Nor does a defendant who transfers the plan to a different victim or target.5OpenCasebook. Model Penal Code (MPC) 5.01 Criminal Attempt
Many states have adopted some version of this defense, with varying requirements. The common thread is that the abandonment must reflect a true moral reversal rather than a tactical retreat.
Why the Test Still Matters
Where an attempt conviction is available, the stakes are real. States generally either reduce the penalty by a fixed amount (California, for example, generally sets attempt at half the prison term for the completed offense), drop the offense down one classification level, or punish attempt at the same grade as the completed crime, as Delaware and Indiana do. Attempted murder is usually carved out for special treatment regardless of the general approach.6Congress.gov. Attempt: An Overview of Federal Criminal Law
The dangerous proximity test has been largely displaced by the substantial step approach, and for understandable reasons: prosecutors and police prefer the ability to intervene earlier in a criminal plan rather than waiting until the defendant is moments from success. The Rizzo outcome frustrates most people’s sense of justice; four armed men spent an afternoon hunting for someone to rob, and the court said that was not enough.
The test endures in legal education and in pockets of case law because it represents a real policy choice. It protects defendants who are still in the thinking-and-planning phase from being swept into attempt liability, and it sets a high bar that reduces the risk of punishing people whose plans might never have materialized. Whether that tradeoff is worth the added public risk is the central debate in attempt law, and the dangerous proximity test sits squarely on one side of it.