Conspiracy to commit armed robbery is a standalone felony built around an agreement between two or more people to carry out a robbery with a weapon. No one has to actually rob anything. Under the federal Hobbs Act, which reaches robberies affecting interstate commerce, the conspiracy alone carries up to 20 years in prison, and the general federal conspiracy statute allows up to five years even when the plan never leaves the planning stage.
What the Prosecution Has to Prove
Every conspiracy conviction rests on a small set of elements that the government must prove beyond a reasonable doubt.
An Agreement Between Two or More People
The agreement is the backbone of the charge. It does not have to be written, spoken aloud, or formal in any way. Prosecutors routinely prove agreements through circumstantial evidence: recorded calls, text messages, surveillance footage, or testimony from someone who was in the room. Coordinated behavior alone can support an inference that an agreement existed, even without anyone ever saying “let’s rob this place.”
Intent to Commit the Robbery
Each defendant must have knowingly and voluntarily joined the agreement with the specific goal of committing armed robbery. Passive awareness that friends are planning something illegal is not enough. Prosecutors show intent through actions like buying weapons, scouting the target, recruiting others, or discussing how to split the proceeds. Someone who drove a friend to a meeting without knowing what was being discussed sits in a very different position from someone who mapped the escape route.
An Overt Act
Under the general federal conspiracy statute, at least one member must take a concrete step toward the robbery. The act itself doesn’t have to be illegal. Buying ski masks, renting a car, or watching the target location all qualify. The overt act is what separates loose talk from a prosecutable conspiracy.
The Hobbs Act works differently. It does not require any overt act. The agreement itself completes the crime, which gives federal prosecutors an easier path when a robbery would affect interstate commerce, and courts read that commerce hook broadly. A convenience store stocking goods shipped from other states can be enough.
The Conspiracy Is Its Own Crime
People sometimes assume that a conspiracy charge disappears if the robbery never happens, or that it merges into the robbery if it does. Neither is true. Conspiracy is a distinct offense. A defendant can be convicted of the conspiracy and the completed robbery, and the sentences can run consecutively. The conspiracy is also complete the moment the agreement (and any required overt act) exists, so an arrest before anyone reaches the target still supports the charge against everyone in the agreement.
Liability for What Your Co-Conspirators Do
One of the harshest features of any conspiracy charge is vicarious liability under the Pinkerton doctrine. Every member of a conspiracy can be held criminally responsible for crimes their co-conspirators commit in furtherance of the agreement, so long as those crimes were reasonably foreseeable. The requirements are that the defendant was part of the conspiracy, the additional crime fell within its scope, the crime was committed to advance the conspiracy, and it was a foreseeable natural consequence of the plan.1Legal Information Institute. Pinkerton Liability
In practice, if a co-conspirator shoots someone during the robbery you helped plan, you can be charged with that shooting even if you were blocks away. Courts have treated violence during an armed robbery as exactly the kind of foreseeable consequence everyone involved should have anticipated. Withdrawing before the crime occurs can cut off future Pinkerton liability, but it does not undo responsibility for anything that already happened.2Justia. Pinkerton v. United States
Federal Penalties
Federal exposure depends on which statute the government uses.
The general federal conspiracy statute caps the sentence at five years and a fine. If the target offense were only a misdemeanor, the conspiracy penalty could not exceed the punishment for that misdemeanor.3Office of the Law Revision Counsel. 18 U.S. Code 371 – Conspiracy to Commit Offense or to Defraud United States Armed robbery is not a misdemeanor, so the full five-year maximum applies.
When the target robbery touches interstate commerce, prosecutors typically charge under the Hobbs Act, which carries up to 20 years.4Office of the Law Revision Counsel. 18 U.S. Code 1951 – Interference With Commerce by Threats or Violence
Firearms add a separate, mandatory layer. Carrying or possessing a firearm during a crime of violence carries a mandatory minimum of five years, served consecutively to any other sentence. Brandishing raises that minimum to seven years, and discharging it raises it to ten.5Office of the Law Revision Counsel. 18 U.S. Code 924 – Penalties These stack on top of whatever the conspiracy or robbery conviction produces, and judges have no discretion to reduce them.
State Penalties
In state court, conspiracy to commit armed robbery is generally a felony. Sentences run from several years to decades, and some states allow life sentences when the plan involved serious threats of violence or multiple victims. Firearm enhancements add years to the base penalty in many states. Fines can reach into the tens of thousands of dollars, and courts frequently order restitution.
How states grade the offense also matters. Some treat the conspiracy at the same felony level as the target crime, so conspiracy to commit a first-degree felony is itself a first-degree felony. Others drop the conspiracy one grade below the target. Identical conduct can produce very different sentences depending on the jurisdiction.
Defenses Worth Knowing
Conspiracy charges are drawn broadly, but they are not unbeatable. The strongest defenses usually attack one of the required elements or raise an affirmative defense.
No Agreement Existed
Because the agreement is the backbone of the charge, showing that no mutual understanding existed can end the case. Being around people who happen to be planning a robbery does not make you a conspirator. The prosecution has to show you actually joined the agreement, not that you were in the room, knew the people involved, or had a vague sense that something illegal was in the air.
Lack of Intent
Even where an agreement existed, each defendant needed the specific intent to facilitate an armed robbery. Someone who did not know the full scope of the plan, or who believed they were part of something else entirely, may fall short of that mental state. Mistake of fact can negate the intent conspiracy requires.6United States Court of Appeals for the Third Circuit. Chapter 8 Final Instructions – Defenses and Theories of Defense
Withdrawal
A defendant who joined but then withdrew can raise that withdrawal as a defense. Withdrawal takes more than a change of heart. Courts look for affirmative steps: clearly telling co-conspirators you are out, or reporting the conspiracy to law enforcement. Simply not showing up is generally not enough.7United States Court of Appeals for the Ninth Circuit. 8.24 Withdrawal From Conspiracy
Timing is decisive. Withdrawal before any overt act can be a complete defense. Withdrawal afterward may limit future liability but does not erase what already happened. The defendant carries the burden of proving withdrawal by a preponderance of the evidence.7United States Court of Appeals for the Ninth Circuit. 8.24 Withdrawal From Conspiracy
Entrapment
Entrapment applies when a government agent pressured someone into joining a conspiracy they otherwise would not have joined. Federal courts apply a subjective test that focuses on the defendant’s predisposition. If the defendant was already inclined toward the crime and law enforcement merely gave an opportunity, the defense fails. If the government manufactured the criminal intent by persistent pressure on someone with no such disposition, entrapment can result in acquittal. Prior convictions are admissible to show predisposition, which makes this defense particularly hard to win for anyone with a record.
Duress
A defendant who joined under an immediate threat of death or serious physical harm may raise duress. The threat must have been imminent, with no reasonable chance to escape or contact police. The defendant carries the burden, and courts examine whether a reasonable person in the same situation would have seen no alternative.8Legal Information Institute. Duress The defense is narrow, but it surfaces in cases involving gang-related conspiracies where participants say they were coerced.
Statute of Limitations
The default federal statute of limitations for conspiracy is five years, running from when the conspiracy ended rather than when it began.9Office of the Law Revision Counsel. 18 U.S. Code 3282 – Offenses Not Capital Conspiracy is treated as a continuing offense, so the clock starts at the last overt act, or when the members have withdrawn or the objectives have been completed or abandoned.
For an individual defendant, proving withdrawal outside the limitations window can bar prosecution entirely. State statutes vary but follow similar logic, running from the conspiracy’s last act rather than its formation.
Charges Commonly Stacked on Top
Conspiracy to commit armed robbery rarely arrives alone. Prosecutors add charges to broaden liability and gain leverage in plea negotiations.
Federal firearms charges are the most common companion. Possessing a firearm in furtherance of a crime of violence carries its own mandatory minimum, served consecutively to any conspiracy or robbery sentence.5Office of the Law Revision Counsel. 18 U.S. Code 924 – Penalties For defendants who are already convicted felons, possession of the firearm is itself an additional federal offense regardless of the robbery.
When the conspiracy involves an ongoing criminal organization, prosecutors may charge racketeering. State-law robbery punishable by more than a year qualifies as a predicate act, as does Hobbs Act robbery.10Office of the Law Revision Counsel. 18 U.S. Code 1961 – Definitions A racketeering conviction carries up to 20 years per count and allows the government to seize assets tied to the enterprise.
Attempted robbery charges often ride along when the group took substantial steps but was intercepted. Burglary can attach if conspirators unlawfully entered a building as part of the plan. Each additional count widens sentencing exposure and gives the government more room in plea negotiations.