Antitrust law generally disfavors tying
arrangements--those in which a vendor conditions the sale of a desired product on the purchase of
another (possibly not-so-desired) product. Not only have tying arrangements been considered
unlawful as violations of Section 1 of the Sherman Act (15 U.S.C. ยง 1), they were determined to be
per se (automatically) unlawful. It was assumed, until at least the late-1970s, first, that such
arrangements were only possible because the seller possessed sufficient market power in the tying
product to allow him to create the tie; and second, that they served no purpose other than the
suppression of competition in the market for the tied (unwanted) product. Then, in U.S. Steel Corp.
v. Fortner Enterprises, Inc. (429 U.S. 610 (1977), Fortner II), the Supreme Court recognized that
there might be a reason other than a seller's ability to "force" a buyer to accept the tie, i.e., that the
fact of buyer acceptance was not necessarily an indication that the seller possessed market power in
the tying product. However, it has continued to be assumed, since the doctrine of patent misuse was
imported into antitrust jurisprudence in International Salt Co. v. U.S. (332 U.S. 392 (1947)), that
because a patent gives the owner a monopoly on the commercial exploitation of the patented product,
it also creates the presumption of sufficient market power to allow the owner to force a tie between
the patented product and some, unpatented product. Congress eliminated that presumption in the
patent area when it amended the Patent Act in 1988; in Illinois Tool Works Inc. v. Independent Ink,
Inc. (547 U.S. ____, No. 04-1329, decided March 1, 2006), the Court eliminated the presumption
in antitrust law: "Today ... we hold that, in all cases involving a tying arrangement, the plaintiff must
prove that the defendant has market power in the tying product." (Slip opinion at 16, emphasis
added.)