Tommy Asher, along with a number of alleged co-conspirators, was charged with conspiring to possess, alter, and transport stolen motor vehicles and with various substantive crimes involving the vehicles. Asher moved to dismiss the conspiracy count on double jeopardy grounds, claiming that he previously had been convicted for participating in the same conspiracy. The district court denied Asher’s motion to dismiss, reasoning that the government’s theory of the case was that the defendant had withdrawn from and subsequently rejoined the conspiracy, thereby subjecting himself to prosecution for a new offense. Asher filed an interlocutory appeal from this ruling, and we now affirm.
I.
Beginning in 1983, Asher participated in a large ear theft ring, which replaced the identification numbers in stolen cars with numbers from wrecked and salvaged vehicles and then sold the ears to unsuspecting consumers. This surreptitious scheme was eventually discovered, and, in 1990, Asher was arrested and charged with conspiracy for his role in the illegal enterprise. Asher pled guilty to the conspiracy charge and, in December of 1990, was sentenced to a term of imprisonment. Asher’s guilty plea, however, may not have been an act of repentance. In 1993, after his release from incarceration, the government alleges that Asher returned to his car-stealing ways and reentered the conspiracy, which had continued in his absence.
On September 14, 1995, Asher and others in the car theft ring were indicted for conspiracy under 18 U.S.C. § 371 and for several substantive crimes. The 1995 indictment alleges that between 1983 and 1994, there was a conspiracy to possess, alter, transport, and sell stolen motor vehicles, in violation of numerous federal statutes. The indictment describes various overt acts, spanning from 1983 through 1993, which were done in furtherance of the conspiracy. Although the conspiracy charge does not expressly state that Asher at any time withdrew from or rejoined the conspiracy, the overt acts alleged in the indictment include Asher’s involvement in the theft of a particular vehicle in 1993, after his release from prison. The indictment also charges Asher with substan *272 tive offenses relating to the theft of this vehicle.
Asher moved to dismiss the conspiracy count, asserting that he had already been convicted for his participation in the same conspiracy and that the conspiracy charge therefore violated the Double Jeopardy Clause of the Fifth Amendment. In response to the motion to dismiss, the government acknowledged that the new conspiracy charge implicated the same car theft ring involved in Asher’s prior conviction, but argued that, after his release from prison, Ash-er reentered the conspiratorial agreement, thereby committing a new offense for which the Double Jeopardy Clause did not bar prosecution. 1 The district court agreed with the government’s position and denied Asher’s motion to dismiss the conspiracy count. The court ruled that the government, in order to convict Asher of the conspiracy charge, would be required to prove that Asher rejoined the stolen vehicle ring after his original conviction. Thus the court held that the government, in accordance with its theory of the case, could only rely on events occurring subsequent to Asher’s original conviction to establish the substantive elements of the charged conspiracy.
II.
On appeal Asher presents two main grounds for reversal of the district court’s decision. First, Asher asserts that the district court constructively amended the indictment. Asher maintains that, as a result, he will be held to answer a charge not contained in the indictment, in violation of the Grand Jury Clause of the Fifth Amendment. . Second, Asher argues that even if the indictment is fairly read as charging his reentry into the conspiracy, the Double Jeopardy Clause prohibits such a charge because he was previously convicted of the same conspiracy.
Before turning to the merits, a word is necessary regarding our jurisdiction in this interlocutory appeal. 28 U.S.C. § 1291 grants us jurisdiction to review all “final decisions” of district courts. It has long been the rule that “final decisions” within the meaning of § 1291 are not limited to final judgments that terminate an action.
See Cohen v. Beneficial Indus. Loan Corp.,
Asher also maintains that the district court violated the Grand Jury Clause by reading a requirement into the indictment that the government prove his reentry into
*273
the stolen vehicle ring after his original conviction. The Grand Jury Clause of the Fifth Amendment provides that “[n]o person shall be held to answer for a capital, or otherwise infamous crime, unless on presentment or indictment of a Grand Jury.” The Supreme Court has held that the Grand Jury Clause grants defendants a “right not to be tried” only where the alleged violation is “so fundamental that it causes the grand jury no longer to be a grand jury, or the indictment no longer to be an indictment.”
Midland Asphalt,
We review the district court’s double jeopardy ruling
de novo. See, e.g., United States v. Furlett,
To support his claim of double jeopardy, Asher relies almost exclusively on the test first set forth in
Blockburger v. United States,
Prosecutions for crimes stemming from a single act do not often create disputes regarding whether a defendant has been prosecuted twice for the same conduct. For example, it is simple enough to determine if a defendant is being prosecuted twice for the same murder or for two different murders. However, the task is not as easy in a conspiracy prosecution, which centers not on a readily apparent “act,” but rather on an agreement to engage in an illegal course of
*274
conduct. Indeed, “the precise bounds of a single conspiracy seldom will be clear from the indictment alone. The gist of the crime of conspiracy and the characteristic which defines its breadth is the unlawful agreement.”
Castro,
Because the essence of a conspiracy is an agreement to commit a crime, “a determination of whether the Government can prosecute on more than one conspiracy rests on whether there exists more than one agreement.”
Dortch
The real problem raised by this case is one of statutory interpretation. Although the Double Jeopardy Clause does not prevent Congress from creating the additional cumulative offense of rejoining a conspiracy, whether Congress did so when it passed 18 U.S.C. § 371 is another matter. The allowable unit of prosecution — “the minimum amount of activity for which criminal liability attaches” — must be determined with reference to the underlying conspiracy statute.
United States v. Allender,
Notes
. A comparison of the information to which Ash-er pled guilty in 1990 and the indictment in the current case clearly reveals that the two prosecutions are based on the same course of illegal conduct. The 1990 information alleged the existence of a conspiracy to traffic in stolen vehicles beginning in April of 1983 and continuing through February of 1987. The current indictment encompasses the time period from 1983 to 1994 and refers to thirteen vehicles that were also included in the overt acts charged in the 1990 information. The 1990 information charged Asher with conspiring to (1) transport stolen vehicles in interstate commerce, in violation of 18 U.S.C. § 2312; (2) remove vehicle identification numbers, in violation of 18 U.S.C. § 511; and (3) possess vehicles with altered identification numbers, in violation of 18 U.S.C. § 2321. The present indictment alleges a conspiracy to commit those three crimes, in addition to (1) operating a chop-shop, in violation of 18 U.S.C. § 2322; (2) possessing stolen vehicles which had crossed state lines, in violation of 18 U.S.C. § 2313; and (3) committing mail fraud, in violation of 18 U.S.C. § 1341.
. To fall within the collateral order exception, an order must (1) "conclusively determine the disputed question,” (2) "resolve an important issue completely separate from the merits of the action,” and (3) “be effectively unreviewable on appeal from a final judgment."
Midland Asphalt,
. For example, the Supreme Court has applied the
Blockburger
test to conclude that the crimes of joyriding and auto theft under Ohio law are the same offense for purposes of the Double Jeopardy Clause.
Brown v. Ohio,
. In this regard, it is important to note that the Double Jeopardy Clause does not prohibit successive prosecutions of an individual for distinct unlawful acts taken within a single course of criminal conduct. Moreover, there is no objective basis for ascertaining the maximum number of permissible statutory offenses implicit in a single course of criminal conduct. Westen & Drubel, Toward a General Theory of Double Jeopardy, 1978 Sup.Ct. Rev. 81, 113. Consequently, "assum[ing] that any particular transaction is made up of a determinable number of constitutional atoms that the legislature cannot further subdivide into separate offenses ... demands more of the Double Jeopardy Clause than it is capable of supplying.”
Whalen v. United States,
