When people get together (that means more than one person) and plan or decide to do something illegal, each member of the group commits the crime. But the additional crime of conspiracy is intended to add additional punishments for the act because the "intention" element required in every crime is specially apparent and obvious. The defenses usually available, of mistake, accident, unintentional are virtually impossible to argue.
Georgia Code Title 16, Section 16-4-8 A person commits the offense of conspiracy to commit a crime when he together with one or more persons conspires to commit any crime and any one or more of such persons does any overt act to effect the object of the conspiracy. A person convicted of the offense of criminal conspiracy to commit a felony shall be punished by imprisonment for not less than one year nor more than one-half the maximum period of time for which he could have been sentenced if he had been convicted of the crime conspired to have been committed, by one-half the maximum fine to which he could have been subjected if he had been convicted of such crime, or both. A person convicted of the offense of criminal conspiracy to commit a misdemeanor shall be punished as for a misdemeanor. A person convicted of the offense of criminal conspiracy to commit a crime punishable by death or by life imprisonment shall be punished by imprisonment for not less than one year nor more than ten years.
Georgia Code Section 16-4-8.1 A person may be convicted of the offense of conspiracy to commit a crime, as defined in Code Section 16-4-8, even if the crime which was the objective of the conspiracy was actually committed or completed in pursuance of the conspiracy, but such person may not be convicted of both conspiracy to commit a crime and the completed crime.
Georgia Code Section 16-4-9 A coconspirator may be relieved from the effects of Code Section 16-4-8 if he can show that before the overt act occurred he withdrew his agreement to commit a crime.