18 U.S.C. § 12

In carrying out the protection of the President of the United States, pursuant to section 3056(a) of title 18, at the one non-governmental property designated by the President of the United States to be fully secured by the United States Secret Service on a permanent basis, as provided in section 3.(a) of Public Law 94–524 [section 3(a) of this note], or at an airport facility used for travel en route to or from such property[,] the Secretary of the Treasury may utilize, with their consent, the law enforcement services, personnel, equipment, and facilities of the affected State and local governments. Further, the Secretary of the Treasury is authorized to reimburse such State and local governments for the utilization of such services, personnel, equipment, and facilities. All claims for such reimbursement by the affected governments will be submitted to the Secretary of the Treasury on a quarterly basis. Expenditures for this reimbursement are authorized not to exceed $300,000 at the one nongovernmental property, and $70,000 at the airport facility, in any one fiscal year: Provided, That the designated site is located in a municipality or political subdivision of any State where the permanent resident population is 7,000 or less and where the absence of such Federal assistance would place an undue economic burden on the affected State and local governments: Provided further, That the airport facility is wholly or partially located in a municipality or political subdivison [sic] of any State where the permanent resident population is 7,000 or less, the airport is located within 25 nautical miles of the designated nongovernmental property, and where the absence of such Federal assistance would place an undue economic burden on the affected State and local governments.”