My understanding is that the term civil conspiracy (in the U.S., at least) normally refers to a crime involving two or more conspirators.

What term is applied to lone conspirators? The Unabomber and D.B. Cooper would be good examples. If they aren't guilty of civil conspiracy, then what term describes their crimes?

To put it another way, how does the law distinguish between a "classic conspiracy" involving two or more people and a crime (or planned crime) involving a lone conspirator?

  • I'm not sure what you mean, if Kaczynski and Cooper are supposed to be examples. They both went beyond planning or "conspiring" to commit crimes; they actually committed them. Cooper actually hijacked a plane. Kaczynski actually mailed bombs which killed people, and he's serving a sentence for bombing and murder, not "conspiracy". – Nate Eldredge Aug 31 '20 at 2:44
  • blogs.findlaw.com/blotter/2017/03/… suggests that your "lone conspirator" could be charged with an attempt to commit the crime, even if they never actually committed it, as long as they carried out some action to prepare for it. If they never did anything but plan, they may not be guilty of anything. This is why police informants usually try to help the suspect make some progress toward the act, instead of just reporting their planning. – Nate Eldredge Aug 31 '20 at 2:46
  • "The Unabomber and D.B. Cooper" might be called "plotters" and so might one who planned an elaborate crime but did not carry it through. They might also be called "felons" or just "criminals". – David Siegel May 13 at 22:02

"Conspiracy" is an agreement between at least two people to undertake some act, and generally refers to an agreement to undertake a criminal act. By definition, then, there is no such thing as a lone conspirator in the same way that there is no such thing as an unmarried wife.

U wants to kill people with bombs sent through the mail. If B agrees to help, U and B are co-conspirators. Iannelli v. United States, 420 U.S. 770 (1975) ("The essence of the crime of conspiracy is agreement.") The very act of agreeing to undertake the crime completes the separate crime of conspiracy, so U and B are correctly labeled co-conspirators.

If U does not recruit B, he is just a guy with an idea, and he has not committed any crime. If he begins to plan to commit the crime, he has still not committed a crime. If he takes a substantial step toward completing the crime, he has committed the offense of attempted murder. United States v. Resendiz-Ponce, 549 U.S. 102 (2007) ("[T]he mere intent to violate a federal criminal statute is not punishable as an attempt unless it is also accompanied by significant conduct.") If he succeeds in carrying out the plan, he has committed murder and is simply called a murderer.

"Civil conspiracy" is not a crime; it is an agreement between at least two people to break the law. That could be an agreement to break the law by committing a crime (e.g., conspiring to kill the president) or it could be an agreement to break the law by committing a civil offense (e.g., publishing defamatory statements).


"Civil conspiracy" in the US refers to a conspiracy between two or more people to commit a non-criminal illegal act such as monopolization or copyright infringement (of course some related acts might also be crimes). This sets civil conspiracy apart from criminal conspiracy.

"Lone conspirator" refers to a (criminal) conspiracy where only one conspirator is in legal jeopardy, for example when a set of individuals are charged with conspiracy to traffic narcotics and all but one are acquitted. There was a rule (the consistency rule) that in that circumstance the sole convicted conspirator's conviction must be reversed, but that rule has been eroded by the federal courts.


A lone person can't commit conspiracy

Conspiracy is its own distinct crime: "[i]f two or more persons conspire either to commit any offense against the United States, or to defraud the United States, or any agency thereof in any manner or for any purpose."

Conspiracy is a "buy one get one free" crime: the Unabomber and D.B. Cooper committed a bunch of crimes but conspiracy wasn't one of them. However, if there were other people involved (which there weren't for the Unabomber but might have been for D.B. Cooper) then they get conspiracy at no extra cost; just an extra charge.

Now, you can attempt pretty much every crime in the book which can cover the early planning stages. You can do this either alone or as part of a conspiracy.

  • 1
    The conpsiracy analysis is generally correct, but I don't think it's correct to say that attempt covers the early planning stages. The general rule is that you have to take a "substantial step" toward completion of the crime. – bdb484 Aug 31 '20 at 4:07
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    On second thought, the "BOGO" characterization is off. Conspiracy liability attaches before you've actually committed a crime, making it the first crime in the series. Following through is a separate crime with resulting in additional legal jeopardy. The federal sentencing guidelines also impose some serious additional costs for bringing someone into your crime that you wouldn't face if you had acted alone. – bdb484 Aug 31 '20 at 4:37

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