son v. Liberty Lobby, Inc., — U.S.-, 106 S.Ct. 2505, 2511-14, 91 L.Ed.2d 202 (1986). We cannot agree, however, that the question of actual malice was properly decided here on summary judgment. The defendants’ motion was not predicated on the absence of a “genuine issue of material fact” as to their state of mind, see Fed.R. Civ.P. 56(c); they instead relied upon the asserted truth of the statement at issue. While district courts possess the authority to enter summary judgment against a party sua sponte, see Celotex Corp. v. Ca-trett, — U.S.-, 106 S.Ct. 2548, 2554, 91 L.Ed.2d 265 (1986), that authority may only be exercised “so long as the losing party was on notice that she had to come forward with all of her evidence.” Id. In this case, McBride was not on notice that he was obliged to marshall evidence establishing a triable issue over the defendants’ actual malice or face summary judgment. Having been afforded no opportunity for discovery into the Science defendants’ state of mind, McBride could hardly have anticipated that the time had come to put up or shut up on the question of their actual malice.3
The district court seems to have believed that disposition of the actual malice issue did not require factual development: i.e., that even accepting as true the facts alleged in McBride’s complaint, the defendants were entitled to judgment as a matter of law. The court maintained that the uncertainty of comparing fees and the ambiguity of the statement indicated that the defendants could not have acted with actual malice. See 613 F.Supp. at 1355. This approach, however, is inconsistent with the substantive standard governing libel suits by public figures. Actual malice refers to a state of mind: the defendant must in fact know the statement to be false, see New York Times, 376 U.S. at 279 — [2]80, 84 S.Ct. at 725-26, or “[in fact] entertain[] serious doubts as to [its] truth,” St. Amant v. Thompson, 390 U.S. 727, 731, 88 S.Ct. 1323, 1325, 20 L.Ed.2d 262 (1968) (emphasis added), or have reckless disregard for whether it is true or false, New York Times, 376 U.S. at 279-80, 84 S.Ct. at 725-26. That a statement might have been made without actual malice does not demonstrate that it was in fact so made. Ambiguity of a statement’s subject matter may be probative evidence negating a finding of actual malice, see Time, Inc. v. Pape, 401 U.S. 279, 290, 91 S.Ct. 633, 639, 28 L.Ed.2d 45 (1971), but it does not call forth a conclusive presumption precluding resort to actual evidence of the defendants’ state of mind. And although a statement’s ambiguity or susceptibility to a “true” construction may make it difficult for a plaintiff to prove that it was made with actual malice, it does not follow that such proof is impossible. Were Doctor McBride, for example, to produce a documentary “smoking gun” in which the defendants admitted that they intended to convey a false impression about his compensation, surely it would have to be conceded that the defendants acted with actual malice. A court simply has no warrant to dismiss a libel suit because it doubts that a jury will ultimately return a verdict for the plaintiff. See Liberty Lobby, 106 S.Ct. at 2514; cf. Hutchinson v. Proxmire, 443 U.S. 111, 120 n. 9, 99 S.Ct. 2675, 2680 n. 9, 61 L.Ed.2d 411 (1979). The district court’s entry of summary judgment based on the absence of actual malice thus cannot be sustained.
While apparently conceding the foregoing, the defendants nonetheless argue that the district court’s judgment may be upheld on alternative grounds. See, e.g., Hoffa v. Fitzsimmons, 673 F.2d 1345, 1362 (D.C.Cir.1982). They repeat their contention, which formed the basis of their summary judgment motion, that the statement about McBride’s fee was “substantially true.” Even more, the defendants argue, McBride’s depositions reveal that the Sci
3
Because we believe that the prerequisites for the entry of summary judgment on the actual malice issue were not satisfied, i.e., a properly supported motion by the defendants or sufficient notice by the district court, we do not reach the question of whether summary judgment should have been denied on the ground of McBride’s lack of opportunity to obtain discovery. See Catrett, 106 S.Ct. at 2554; Liberty Lobby, 106 S.Ct. at 2511 n. 5; Fed.R.Civ.P. 56(f).