For purposes of subsection (a), a person shall not be considered to have engaged in business activities within a State during any taxable year merely by reason of sales in such State, or the solicitation of orders for sales in such State, of tangible personal property on behalf of such person by one or more independent contractors, or by reason of the maintenance, of an office in such State by one or more independent contractors whose activities on behalf of such person in such State consist solely of making sales, or soliciting orders for sales, or tangible personal property.
15 U.S. Code § 381. Imposition of net income tax
Title II of Pub. L. 86–272, as amended by Pub. L. 87–17, Apr. 7, 1961, 75 Stat. 41; Pub. L. 87–435, Apr. 21, 1962, 76 Stat. 55; Pub. L. 88–42, June 21, 1963, 77 Stat. 67; Pub. L. 88–286, Mar. 18, 1964, 78 Stat. 166, and repealed by Pub. L. 94–455, title XXI, § 2121(a), Oct. 4, 1976, 90 Stat. 1914, provided for a study by the Committee on the Judiciary of the House of Representatives and the Committee on Finance of the United States Senate, acting separately or jointly, or any duly authorized subcommittee thereof, of all matters pertaining to the taxation of interstate commerce by the States, territories, and possessions of the United States, the District of Columbia, and the Commonwealth of Puerto Rico, or any political or taxing subdivision of the foregoing, and for a report together with their proposals for legislation on or before June 30, 1965.