The 5th Amendment to the US Constitution:

"No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation."

 

The 'Lectric Law Library's Lexicon On Double Jeopardy

DOUBLE JEOPARDY - Being tried twice for the same offense; prohibited by the 5th Amendment to the U.S. Constitution. '[T]he Double Jeopardy Clause protects against three distinct abuses: [1] a second prosecution for the same offense after acquittal; [2] a second prosecution for the same offense after conviction; and [3] multiple punishments for the same offense.' U.S. v. Halper, 490 U.S. 435, 440 (1989).

Separate punishments in multiple criminal prosecution are constitutionally permissible, however, if the punishments are not based upon the same offenses. In Blockburger v. U.S., 284 U.S. 299 (1932), the Supreme Court held that punishment for two statutory offenses arising out of the same criminal act or transaction does not violate the Double Jeopardy Clause if 'each provision requires proof of an additional fact which the other does not.' Id. at 304.

More recently, in U.S. v. Dixon, 113 S.Ct. 2849, 2856 (1993), the Court clarified the use of the 'same elements test' set forth in Blockburger when it over-ruled the 'same conduct' test announced in Grady v. Corbin, 495 U.S. 508 (1990), and held that the Double Jeopardy Clause bars successive prosecutions only when the previously concluded and subsequently charged offenses fail the 'same elements' test articulated in Blockburger. See also Gavieres v. U.S., 220 U.S. 338, 345 (1911) (early precedent establishing that in a subsequent prosecution '[w]hile it is true that the conduct of the accused was one and the same, two offenses resulted, each of which had an element not embraced in the other').

In U.S. v. Felix, 112 S.Ct. 1377 (1992), the Court held that 'prosecution of a defendant for conspiracy, where certain of the overt acts relied upon by the Government are based on substantive offenses for which the defendant has been previously convicted, does not violate the Double Jeopardy Clause.' Felix, at 1380. See also Saccoccia, 18 F.3d at 798 (citing Felix, at 1384) ('A substantive crime and a conspiracy to commit that crime are not the same offense for double jeopardy purposes.')

The Double Jeopardy Clause protects against multiple punishments for the same offense. Justices of Boston Municipal Court v. Lydon, 466 U.S. 294, 306 (1984).

However, stretching the bounds of logic, the courts have decided that since the state and federal governments are separate sovereigns and therefore successive prosecutions based on the same underlying conduct do not violate the Double Jeopardy Clause if the prosecutions are brought by separate sovereigns. See, e.g., U.S. v. Koon, 34 F.3d 1416, 1438 (9th Cir.'94).

But, double jeopardy may exist if the federal prosecutors were mere 'tools' of the state or that the federal proceeding was a 'sham' carried out at the behest of the state. Koon, at 1438.

Close coordination between state and federal authorities, including 'the employment of agents of one sovereign to help the other sovereign in its prosecution,' does not implicate the Double Jeopardy Clause. U.S. v. Figueroa-Soto, 938 F.2d 1015, 1020 (9th Cir.'91), cert. denied, 502 U.S. 1098 (1992); accord U.S. v. Paiz, 905 F.2d 1014, 1024 (7th Cir.'90), cert. denied, 499 U.S. 924 (1991) (holding that the fact 'that an Indiana prosecutor was later designated a Special Deputy United States Attorney for purposes of a federal prosecution' was insufficient to establish a sham prosecution). Nor is a county's possible pecuniary interest in a federal proceeding sufficient to transform the federal government into a mere 'tool' of the county.

http://www.lectlaw.com/def/d075.htm