The Congress of the United States of America consents that any of the States in which tobacco is produced may negotiate a compact or compacts for the purpose of regulating and controlling the production of, or commerce in, any one or more kinds of tobacco therein: Provided, That all State acts authorizing such compact or compacts shall be essentially uniform and in no way conflicting: Provided further, That any compact, compacts, agreement, or agreements negotiated and agreed upon by the States referred to in the Act of the General Assembly of Virginia, approved March 13, 1936 (known as the Tobacco Control Act) (Va. Code 1936, Sec. 1399), or by any other State or States producing any type or types of tobacco referred to in said Act, which is in conformity with said Act and relating to the type or types of tobacco specifically referred to in said Act, shall become effective to the extent and in the manner provided for in said Act without further consent or ratification on the part of the Congress of the United States of America: Provided, however, That nothing herein contained shall be construed as preventing the Congress of the United States of America from withdrawing its consent after April 25, 1936, to any compact or agreement entered into pursuant to this chapter: Provided further, That nothing in said sections shall be construed to grant the consent of Congress to negotiate any compact for regulating or controlling the production of, or commerce in, tobacco for the purpose of fixing the price thereof, or to create or perpetuate monopoly, or to promote regimentation, but such consent shall be limited to compacts for the regulation and control of production of, or commerce in, tobacco in order thereby to enable growers to receive a fair price for such tobacco