The 1914 Clayton Act prohibited any acquisition whose effect may be to “substantially” lessen competition. International Shoe defined § 7's word “substantially” by saying that an acquisition's effect is “substantial” only if it “will injuriously affect the public.” This paper...

Despite enormous changes in factors affecting milk supply and demand, total fluid milk consumption has been essentially constant since 1944 in the U.S. (since 1961 in the E.U.). Classical economic analysis cannot explain persistently constant consumption in dramatically changing markets....