The Illustrated Guide to Criminal Law
Chapter 10: We’ll All Go Down Together
Conspiracy pg 24: The Crime of Agreement
With Conspiracy, what’s criminal is not any particular act, but the mere agreement between people to commit a crime. In other words, agreeing to commit a crime is itself deemed dangerous enough to society to be punishable.
Two conspirators in 16th-century attire, on a table bench.
CONSPIRATOR A
So we’re agreed. Next Monday, we go to the Duke’s palace…
CONSPIRATOR B
…Yes, yes! And we steal all the chickens!
CONSPIRATOR A
Do what? Okay, maybe we’re not in agreement just yet.
Some laws require nothing more than the mere agreement. That was the common law definition of the crime. But today, most laws require something more—that at least one of the conspirators committed an “overt act” in furtherance of the conspiracy.
Average Joe looking perplexed
AVERAGE JOE
People usually say “co-conspirators” instead of just “conspirators.” But the “co” always strikes me as redundant.
If I conspire with Jane, and Bob conspires with Susan, then both I and Bob are conspirators; but we’re not co-conspirators. However, Bob and Susan are co-conspirators; they conspired with each other.
Thus “co-conspirators” conveys the clarity that two parties have not merely conspired, but conspired with each other.
I agree with you in principle, as I too enjoy the elegance of the usage, but I do not think the majority of english speakers employing the term are using in in that sense.
To the contrary, I checked the usage in the Corpus of Historical American English (COHA) and this usage is commonplace. People use “co-conspirator” to describe a conspirator who’s involved with either a previously mentioned conspirator or previously mentioned conspiracy. If you’re a “conspirator” you conspire in general, but if you’re a “co-conspirator” you’re part of the conspiracy in question, or more often, conspiring together with the other person or persons being discussed.
Conspirator is a bit like “member of a class” while co-conspirator is like “classmate.” Common usage does support it.