174 Opinion of the Court. II. First it may be helpful to set out what is not involved in this case. There is no claim by the Government that it is illegal for one merely to acquire a patent in order to exclude his competitors; or that the owner of a lawfully acquired patent cannot use the patent laws to exclude all infringers of the patent; or that a licensee cannot lawfully acquire the covering patent in order better to enforce it on his own account, even when the patent dominates an industry in which the licensee is the dominant firm. Therefore, we put all these matters aside without discussion. What is claimed here is that Singer engaged in a series of transactions with Gegauf and Vigorelli for an illegal purpose, i. e., to rid itself and Gegauf, together, perhaps, with Vigorelli, of infringements by their common competitors, the Japanese manufacturers. The Government claims that in this respect there were an identity of purpose among the parties and actions pursuant thereto that in law amount to a combination or conspiracy violative of the Sherman Act. It claims that this can be established under the findings of the District Court. We note from the findings that the importation of Japanese household multicam zigzag sewing machines first came to notice in the United States in 1954 with the introduction of such a machine by the Brother International Corporation. It incorporated the mechanism of the Vigorelli zigzag and the Singer 401 machines. By 1959 importations of all Japanese household sewing machines reached 1,100,000, while importations of European machines reached only 100,000. Moreover, it appears that all but two domestic manufacturers were put out of business in three to four years after the Japanese machines first appeared. The two remaining domestic manufacturers were Singer and a company not specializing in sew Opinion of the Court. 374 U.S. ing machines, which manufactured only straight stitch machines on order for a single domestic customer. The trial court found that no mention was made of the Japanese machines during the negotiations covering the Vigorelli cross-licensing agreement with Singer. It first appeared during the Gegauf licensing negotiations where at those meetings Singer used "protection against the Japanese" as "one of the strong points" on the crosslicensing of the Gegauf and Harris patents and applications. Here, though the trial court stated that the "dominant and sole purpose of the license agreement was to settle the conflict in priority," it specifically, in the next paragraph of its opinion, found a "secondary" purpose, i. e., protection against the Japanese machines which were infringing the Gegauf patent. In this connection it is most important to note another finding of the trial court, namely, that this purpose to exclude the Japanese "was the only one disclosed to Gegauf, and in fact the very one used to convince Gegauf of the advisability of entering into an agreement." 205 F. Supp., at 413. Under these findings it cannot be said that settlement of the conflict in priority was the "dominant and sole purpose" of Singer. Indeed, the two findings are in direct conflict. Furthermore the fact that the cross-license agreement provided that Singer and Gegauf would facilitate the allowance to each other of claims "as broad as possible" indicates a desire to secure as broad coverage for the patent as possible, the more effectively to stifle competition, the overwhelming percentage of which was Japanese. This effect was accomplished, for when the Patent Office placed the Harris (Singer) and Gegauf patents in interference, Singer abandoned the proceeding, thus facilitating the issuance of broad claims to Gegauf." 7 Since we have concluded that the entire course of dealings between the parties, including the cross-license agreement, establishes a conspiracy or combination in violation of the Sherman Act, we need not 174 Opinion of the Court. We now come to the assignment of the Gegauf patent to Singer. The trial court found: (1) that six days after the license agreement was made with Gegauf, Singer proceeded to Italy where a conference was held with Vigorelli. At this meeting two events took place that led to the later acquisition of the patent by Singer. The first was Vigorelli's proposal that Singer, Gegauf and himself act "in concert against others" in enforcing the patent. This was rejected by Singer's representatives, who said it was best for each "to prosecute his own patents." At the same meeting, however, Singer proposed to Vigorelli that it could prosecute the Gegauf patent in the United States better than Gegauf and, after Vigorelli agreed, solicited his help in getting Gegauf to agree to assign the patent. (2) Vigorelli went to Gegauf "acting as Singer's agent," 205 F. Supp., at 414, and convinced the latter sufficiently for him to write Singer that he favored the idea of doing something "against Japanese competition." (3) Singer replied to Gegauf by letter that an arrangement could be reached "equally advantageous to both." (4) Singer went to Europe but was not able to agree on Gegauf's terms and thereafter, in September 1957, wrote the latter that "their mutual interests required that something be done to protect themselves from the Japanese infringing machines." (5) Gegauf replied that he would be happy to meet Singer to discuss "mutual enforcement" of its United States application and the Harris reissue. Then, (6) in the final conferences in Europe Gegauf told Singer that he had no objection "to making an agreement with Singer, in order to stop as far as possible Japanese competitors in the United States market." Further, the trial court found that Singer assured Gegauf that "Singer was in and do not pass on the Government's contention that the crosslicense agreement and the interference settlement are illegal apart from the other circumstances present here. As to this question, see Note, 31 Geo. Wash. L. Rev. 643 (1963). 699-272 O-63-16 Opinion of the Court. 374 U.S. surance against common competitors" and Gegauf's fears that if Singer stopped the Japanese infringements in the United States they (the Japanese) would go to Europe, where Gegauf was not in as good a position to stop them, were unfounded because a greater risk was run in Europe if Singer were not permitted to first stop infringements in the United States. Finally, the court found that (7) Singer was determined "to drive home the point" that Gegauf stood to benefit more by enforcement of the patents in the United States because the "Brother Pacesetter" machine, a big selling and patent infringing Japanese-made machine, was in direct competition with the Gegauf machine in the United States. As the trial court put it, "[t]he point apparently reached home"Gegauf ultimately assigned the patent for only $90,000, much less than its original asking price and much less than Gegauf believed it would realize annually from a license grant. Gegauf's beliefs as to the inadequacy of the monetary consideration were well founded, since Singer received more than twice that amount in a twoyear period from the one license it granted under the Gegauf patent. That license, incidentally, was to Sears, Roebuck & Company, which imported machines from Europe. III. As we have noted with reference to the cross-license agreement, the trial court decided that "[t]he undisputed facts support no conclusion other than that the underlying, dominant and sole purpose of the license agreement was to settle the conflict in priority between the Gegauf and Harris patents . . . . We have rejected this conclusion on the trial court's own finding in the next paragraph of the opinion that Singer's "secondary" purpose, the only one disclosed to Gegauf, was its "desire to obtain protection against the Japanese machines which might be made under the Gegauf patent." Likewise we reject, 174 Opinion of the Court. as a question of law, the court's inference that the attitude of suspicion, wariness and self-preservation of the parties negated a conspiracy. See United States v. Line Material Co., 333 U. S. 287, 297 (1948); United States v. Masonite Corp., 316 U. S. 265, 280-281 (1942); United States v. General Electric Co., 80 F. Supp. 989, 997-998 (S. D. N. Y. 1948). The trial court held that the fact that Singer had a purpose, which "Gegauf well knew," of enforcing the patent upon its acquisition, that the enforcement "would most certainly include Japanese manufacturers who were the principal infringers," and "that Gegauf shared with Singer a common concern over Japanese competition" did not establish a conspiracy. 205 F. Supp., at 419. Given the court's own findings and the clear import of the record, it is apparent that its conclusions were predicated upon "an erroneous interpretation of the standard to be applied. . . ." Thus, "[b]ecause of the nature of the District Court's error we are reviewing a question of law, namely, whether the District Court applied the proper standard to essentially undisputed facts." United States v. Parke, Davis & Co., 362 U. S. 29, 44 (1960). There in a discussion of a like problem we held that "the inference of an agreement in violation of the Sherman Act" is not "merely limited to particular fact complexes," ibid., citing United States v. Bausch & Lomb Optical Co., 321 U. S. 707 (1944), and Federal Trade Comm'n v. Beech-Nut Packing Co., 257 U. S. 441 (1922). "Both cases," the Court continued, "teach that judicial inquiry is not to stop with a search of the record for evidence of purely contractual arrangements. . . ." Ibid. Whether the conspiracy was achieved by agreement, by tacit understanding, or by "acquiescence coupled with assistance in effectuating its purpose is immaterial." United States v. Bausch & Lomb, supra, at 723. Here the patent was put in Singer's hands to |