Assimilative Crimes Act (ACA) is a Federal statute (18 U.S.C.A. § 13) which provides adoption by Congress of state criminal laws for areas of exclusive or concurrent federal jurisdiction if the crime is not punishable under federal law. In short, when a criminal offense has been committed on land or buildings that have been reserved or acquired by the federal government, and the offense is not a federal offense, state law will apply to the offense under the Assimilative Crimes Act. When the federal government prosecutes the offense, it is not enforcing state law but is enforcing the federal law by incorporating or by applying the state law to the offense. This statute uses local laws as gap-fillers for federal criminal law.
The Act applies to state laws validly existing at the time of the offense without regard to when these laws were enacted, whether before or after passage of the Act, and whether before or after the acquisition of the land where the offense was committed. For example, when a murder is committed on land that is owned by the federal government, the federal government will apply the elements for murder under state law because murder is not a federal offense.
The ACA has also been used to assimilate state laws that prohibit driving under the influence of alcohol, and courts have had to resolve a variety of issues regarding the assimilation of such laws. For example, courts have disagreed as to whether state statutes against driving under the influence of alcohol may be assimilated by the ACA if violations of such statutes are not considered to be crimes under state law but are merely subject to civil or administrative penalties. The court in U.S. v. Devenport, 131 F.3d 604, 175 A.L.R. Fed. 709 (7th Cir. 1997), held that such noncriminal state statutes cannot be assimilated by the ACA.
The text of the Act is as follows:
18 USCS § 13. Laws of States adopted for areas within Federal jurisdiction
(a) Whoever within or upon any of the places now existing or hereafter reserved or acquired as provided in section 7 of this title [18 USCS § 7], or on, above, or below any portion of the territorial sea of the United States not within the jurisdiction of any State, Commonwealth, territory, possession, or district is guilty of any act or omission which, although not made punishable by any enactment of Congress, would be punishable if committed or omitted within the jurisdiction of the State, Territory, Possession, or District in which such place is situated, by the laws thereof in force at the time of such act or omission, shall be guilty of a like offense and subject to a like punishment.
(b) (1) Subject to paragraph (2) and for purposes of subsection (a) of this section, that which may or shall be imposed through judicial or administrative action under the law of a State, territory, possession, or district, for a conviction for operating a motor vehicle under the influence of a drug or alcohol, shall be considered to be a punishment provided by that law. Any limitation on the right or privilege to operate a motor vehicle imposed under this subsection shall apply only to the special maritime and territorial jurisdiction of the United States.
(2) (A) In addition to any term of imprisonment provided for operating a motor vehicle under the influence of a drug or alcohol imposed under the law of a State, territory, possession, or district, the punishment for such an offense under this section shall include an additional term of imprisonment of not more than 1 year, or if serious bodily injury of a minor is caused, not more than 5 years, or if death of a minor is caused, not more than 10 years, and an additional fine under this title, or both, if--
(i) a minor (other than the offender) was present in the motor vehicle when the offense was committed; and
(ii) the law of the State, territory, possession, or district in which the offense occurred does not provide an additional term of imprisonment under the circumstances described in clause (i).
(B) For the purposes of subparagraph (A), the term "minor" means a person less than 18 years of age.
(c) Whenever any waters of the territorial sea of the United States lie outside the territory of any State, Commonwealth, territory, possession, or district, such waters (including the airspace above and the seabed and subsoil below, and artificial islands and fixed structures erected thereon) shall be deemed, for purposes of subsection (a), to lie within the area of the State, Commonwealth, territory, possession, or district that it would lie within if the boundaries of such State, Commonwealth, territory, possession, or district were extended seaward to the outer limit of the territorial sea of the United States.