William J. Brennan, Jr.

“ If the defense of illegality is to be allowed as a collateral method of enforcement of the antitrust laws, as the breadth of the petitioner's argument suggests, it must be said that his theory creates a very strange class of private attorneys general.
In any event, an analysis of the narrow scope in which the defense is allowed in respect of the Sherman Act indicates that the principle of distinction is not what the petitioner claims it to be. The leading case here in which the defense was allowed is Continental Wall Paper Co. ”

“ Accordingly, while the nondelivery agreement between the parties could not be enforced by a court, if its unlawful character under the Sherman Act be assumed, it can hardly be said to enforce a violation of the Act to give legal effect to a completed sale of onions at a fair price. ”

“ The petitioner and the other growers, who usually sold through trade channels, were fearful that this would cause them considerable loss. It was finally agreed by the petitioner and other growers that they would purchase 287 of the 600 cars of onions stored in the Chicago area, and the respondent and Siegel agreed not to deliver any onions on the futures market for the remainder of the current trading season. The petitioner and the other purchasers themselves agreed not to deliver any of the onions purchased from respondent and Siegel on the futures market for the remainder of the season ”