system: You are a legal assistant. Answer concisely and accurately. When legal text is provided, rely on it and do not invent facts.

user: Read the following U.S. Supreme Court case excerpt and classify it into the correct legal issue area. Excerpt: 360 U.S. 712 79 S.Ct. 1443 3 L.Ed.2d 1539 WISCONSIN et al.v.ILLINOIS et al. MICHIGAN v. ILLINOIS et al. NEW YORK v. ILLINOIS et al. ILLINOIS v. MICHIGAN et al. Nos. 2, 3, 4, 15, Original. Supreme Court of the United States June 29, 1959 [Syllabus intentionally omitted] Messrs. William C. Wines, Asst.Atty.Gen., and Charles A. Bane (Messrs. Latham Castle, Atty.Gen., George E. Billett and Calvin D. Trowbridge, Special Asst.Attys.Gen., on the brief), for the Stat of Illinois. Messrs. Stewart G. Honeck, John Reynolds, Attys.Gen., and Roy G. Tulane, Asst. Atty.Gen., for the State of Wisconsin. Messrs. Miles Lord, Atty.Gen., Melvin J. Peterson, Deputy Atty.Gen., and Raymond A. Haik, Special Asst.Atty.Gen., for the State of Minnesota. Messrs. William Saxbe, Mark McElroy, Attys.Gen., Robert E. Boyd and J. Harold Read, Asst.Attys.Gen., for the State of Ohio. Mr. Thomas D. McBride, Anne X. Alpern, Attys.Gen., and Lois G. Forer, Deputy Atty.Gen., for the State of Pennsylvania. Mr. Herbert H. Naujoks, Special Asst. to the Attorneys General. Messrs. Paul L. Adams, Atty.Gen., Samuel J. Torina, Sol.Gen., and Nicholas V. Olds, Asst.Atty.Gen., for the State of Michigan. Solicitor General Rankin (Messrs. Oscar H. Davis, John F. Davis and George S. Swarth, on the brief), for the United States, as amicus curiae in No. 15. Messrs. Louis J. Lefkowitz, Atty.Gen., Richard H. Shepp, Dunton F. Tynan, Asst.Atty.Gen. (Mr. John R. Davison, on the brief for the Power Authority of New York), for the State of New York. Messrs. Latham Castle, Atty.Gen. of Illinois, William C. Wines, Asst.Atty.Gen., George A. Lane, Lawrence J. Fenlon, Joseph B. Fleming, Joseph H. Pleck and Thomas M. Thomas, for defendants in Nos. 2, 3, 4. Solicitor General Rankin, Messrs. John F. Davis and George S. Swarth, for the United States, as amicus curiae in Nos. 2, 3, 4. Messrs. Sydney G. Craig and David M. Gooder, for Chicago Association of Commerce and Industry, as amicus curiae in Nos. 2, 3, 4. PER CURIAM. 1 The motion of Chicago Association of Commerce and Industry for leave to file brief in Nos. 2, Original, 3, Original and 4, Original, as amicus curiae, is granted. The amended application of complainants for a reopening of the decree of April 21, 1930, in Nos. 2, Original, 3, Original, and 4, Original, is granted. 2 The motion for leave to file a bill of complaint in No. 15, Original, is granted. 3 It is ordered that Honorable Albert B. Maris, United States Senior Circuit Judge, be, and he is hereby, appointed special master in each of these causes, with authority to summon witnesses, issue subpoenas, and take such evidence as may be introduced and such as he may deem it necessary to call for. The master is directed to hold hearings with all convenient speed, and to submit such reports as he may deem necessary. 4 The master shall be allowed his actual expenses. The allowances to him, the compensation paid to his technical, stenographic and clerical assistants, the cost of printing his report, and all other proper expenses, shall be charged against and be borne by the parties in such proportion as the Court hereafter may direct.

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