s Corp., 319 U.S. 671, 688 n. 24 (1943); New State Ice Co. V. Liebmann, 285 U.S. 262, 292-94 (1932) (Brandeis, J., dissenting)). Economists and the Supreme Court have largely rejected ruinous competition a basis for regulation. 12 (Indeed, then-Harvard law professor and now-Justice Stephen Breyer (1982) criticized this rationale as an "empty box" with no particular economic meaning or content.) Any excess capacity that might exist would only lead firms to forego making new investments as the existing capital stock was depreciated. Thus, although producing firms might suffer substantial losses in the short run, over the long run the market would tend toward the competitive equilibrium. In the meantime, the ensuing competition would yield substantial benefits to consumers, while simultaneously identifying the most efficient firm from among the contenders On the breakup of AT&T, see Modification of Final Judgment, 552 F. Supp. at 180-86, 189-90. On the Telecommunications Act of 1996, see 47 U.S.C. §§ 272(a)(2)(C), 274, 275. See Hovenkamp (1991) for a survey of the intellectual history of "ruinous competition." 12 For judicial rejections of ruinous competition, see Arizona V. Maricopa County Medical Soc'y, 457 U.S. 332, 346 (1982); Nat'l Soc'y of Prof'l Eng'rs V. United States, 435 U.S. 679, 689-90 (1978); United States V. Container Corp. of Am., 393 U.S. 333, 338 n.4 (1969); Fashion Originators' Guild of Am. V. FTC, 312 U.S. 457 (1941); United States V. Socony-Vacuum Oil Co., 310 U.S. 150, 220-24 (1940); United States V. Trans-Mo. Freight Ass'n, 166 U.S. 290 (1897). The sole modern exception is Appalachian Coals, Inc. V. United States, 288 U.S. 344 (1933), which allowed competing coal producers to form an agreement that limited competition SO long as the intent was not to unreasonably restrain trade. That holding does not seem to have withstood the test of time. For statements by economists rejecting ruinous competition, see, e.g., Clark (1914); Knight (1921a); Taussig (1922); Clark (1923); Kaysen and Turner (1959);