concurring in the judgment:
Although I concur in the result of this case, I do not agree with the majority’s conclusion that there was insufficient evidence from which a reasonable jury could have found that Brown’s retaliatory ani*810mus was a “substantial or motivating factor,” see Gilbrook v. City of Westminster, 177 F.3d 839, 853 (9th Cir.1999), in Fuller’s decision to terminate Scott. As the majority intimates, a supervisor who, with retaliatory intent, selectively reports an employee to a superior is liable for the employee’s termination even if the supervisor does not influence the resulting investigation or termination decision. See Maj. Op. at 804-05. In this case, the majority concludes that Brown discovered Scott’s journal and reported it to Fuller while “engaged in activities typical and appropriate for her position,” and then states that Scott does not allege that Brown “targeted her for investigation or selectively reported her misconduct.” See id. But Scott obviously does so allege, she has maintained from the outset — and the jury must have found — that Brown reported her to Fuller for a retaliatory reason. The difference between targeting someone for investigation and retaliating against them by reporting them, knowing they would thereupon be investigated, entirely escapes me. So, the majority can only be holding that any retaliatory animus that Brown harbored against Scott did not motivate her decision to report Scott to Fuller, and that a reasonable jury could not have concluded otherwise.
I disagree. I would hold that Scott met her burden of establishing that Brown’s retaliatory animus was a “substantial or motivating factor” in Fuller’s decision to terminate Scott. See Gilbrook, 177 F.3d at 853. The majority’s implicit conclusion to the contrary — that Brown was not motivated by retaliatory reasons but was just doing her job — disregards our mandate to view “the evidence in the light most favorable to the party in whose favor the jury returned a verdict and draw all reasonable inferences in her favor,” and fails to accord the required deference to a reasonable jury decision. Maj. Op. at 802 (citing Os-tad v. Oregon Health Sci. Univ., 327 F.3d 876, 881 (9th Cir.2003)); see also id. (“Judgment as a matter of law is proper when the evidence permits only one reasonable conclusion and the conclusion is contrary to that reached by the jury.”).
Alternatively, the majority can possibly be read as holding that a supervisor, even if motivated by retaliatory animus, may not be held liable for instigating an investigation likely to result in an adverse action, as long as the superior who makes the final decision does so independently. If so, the holding squarely conflicts with Gil-brook, which held to the contrary.
At the same time, the facts of this case indicate that Fuller’s investigation would have occurred even without Brown’s instigation. I would therefore hold that Brown also met her burden, under part two of the two-part Gilbrook/Mt. Healthy burden-shifting framework, of showing that Scott’s discharge would have occurred “even in the absence of the protected conduct.” See Gilbrook, 177 F.3d at 854; Maj. Op. at 803, 807-08. My decision to reverse the judgment, in other words, rests on Brown’s successful affirmative defense, not on Scott’s failure to establish her initial case.
A. The “Substantial or Motivating Factor” Requirement
Under the two-part burden-shifting framework outlined by the Supreme Court in Mt. Healthy City School District Board of Education v. Doyle, 429 U.S. 274, 97 S.Ct. 568, 50 L.Ed.2d 471 (1977), and applied by this Court in Gilbrook, the plaintiff bears the initial burden of demonstrating that her protected conduct was a “ ‘substantial’ or ‘motivating’ factor in the defendant’s employment decision.” Gilbrook, 177 F.3d at 853-54 (quoting Mt. Healthy, 429 U.S. at 287, 97 S.Ct. 568). *811Once the plaintiff makes this showing, the burden shifts to the defendant to show “ ‘by a preponderance of the evidence that it would have reached the same decision ... even in the absence of the plaintiffs protected conduct.’ ” Id. (quoting Mt. Healthy, 429 U.S. at 287, 97 S.Ct. 568).
In this case, as in Gilbrook, the defendant is the supervisor who initially reported the plaintiffs misconduct, not the employer or the individual who made the ultimate decision to terminate. See Gilbrook, 177 F.3d at 853-54. For this reason, vicarious liability eases such as Poland v. Chertoff, 494 F.3d 1174 (9th Cir.2007), are, contrary to the majority’s reliance on them, not analogous. Those cases are concerned with identifying situations in which it would be equitable to hold an otherwise faultless superior liable for the acts of an admittedly culpable subordinate. See SpeiseR et. al, The AMERICAN Law of Torts § 4:1 (“[Vicarious liability] is an interesting form of social policy adjustment under which, even though a person ... is himself personally without fault, legal public policy renders him nevertheless liable.”). As a result, the focus of vicarious liability cases is properly on the actions of the superior, and therefore on whether those actions were tainted by the subordinate’s animus.
In addition, vicarious liability cases implicate very different policy considerations than subordinate liability cases, particularly with respect to the protection of an employee’s First Amendment rights. In the vicarious liability context, the concern is that, in the absence of a rule imposing vicarious liability, an employer could evade liability by isolating the final deeision-maker and, in essence, willfully ignoring the bias of a subordinate. Thus, the inquiry in a vicarious liability case is into whether the superior’s investigation and termination decision were truly independent.
By contrast, the concern in a subordinate liability case is that too lenient a standard will permit supervisors deliberately to target individuals who have engaged in protected activity, knowing that their actions will lead superiors lacking retaliatory animus to harm the individual. The issue is not, in other words, whether the employer is acting with willful ignorance (which an “independent investigation” requirement is good at measuring), but rather whether the subordinate supervisor is deliberately placing the subordinate in the way of harm (which the “independent investigation” requirement only partly measures). Accordingly, as will appear, the inquiry in a subordinate liability case is broader, requiring not only a determination as to whether the investigation and termination decision were influenced by the biased subordinate, but also whether the subordinate initiated those proceedings in retaliation for the employee’s protected activity.
The focus in a case such as this one, then, must be on the supervisor’s conduct — specifically on whether that conduct (a) was a “substantial or motivating factor” in the employee’s termination, and (b) was motivated by retaliatory animus.
I agree with the majority that, on this record, Brown did not in any substantial way influence Fuller’s investigation once it began, or Fuller’s ultimate decision to terminate Scott.1 See Maj. Op. 807-08. *812Brown’s conduct after she reported the journal to Fuller was therefore not a cause of Scott’s termination, regardless of its motivation.
But Brown’s lack of participation in Fuller’s investigation and decision to terminate does not end the causation inquiry.2 Rather, we must also consider whether Brown, while acting with retaliatory animus, “set[] in motion a series of acts by others which [she knew] or reasonably shouldfhave known] would cause others to inflict the constitutional injury.” See Gilbrook, 177 F.3d at 854 (noting that the “requisite causal connection can be established not only by some kind of direct personal participation in the deprivation, but also by setting in motion a series of acts by others which the actor knows or reasonably should know would cause others to inflict the constitutional injury”) (quoting Johnson v. Duffy, 588 F.2d 740, 743-44 (9th Cir.1978)); see also Restatement (seoond) of ToRts § 433 (1965) (“The following considerations are ... important in determining whether the actor’s conduct is a substantial factor in bringing about harm to another: ... (b) whether the actor’s conduct has created a force or series of forces which are in continuous and active operation up to the time of the harm.”).3
It is undisputed that Fuller launched the investigation that led to Scott’s termination immediately after Brown presented her with Scott’s journal. Because Scott’s journal contained significant evidence of misconduct, Brown either knew or should have known that presenting the journal to Fuller would “set[] in motion a series of acts” by Fuller that “would cause [Fuller] to inflict the constitutional injury,” i.e., to terminate Scott. See Gilbrook, 177 F.3d at 854. As a result, Brown’s act of reporting Scott to Fuller was a “cause” of Scott’s termination, even though she did not “directly] ... participate]” in the ultimate decision to terminate. See Gilbrook, 177 F.3d at 854; see also Restatement (Second) of Torts §§ 433, 441, 442A.
*813The majority appears to suggest, however, that Brown’s decision to report the journal to Fuller cannot support Scott’s claim, because Brown discovered the journal and brought it to Fuller’s attention while she was “engaged in activities typical and appropriate for her position.” Maj. Op at 805. As a result, the majority suggests, any retaliatory animus Brown harbored against Scott could not be, as a matter of law, a “substantial or motivating factor” in Scott’s discharge. Maj. Op. at 807-08.
Although the evidence could support the majority’s interpretation, it does not foreclose the opposite conclusion. See Ostad, 327 F.3d at 881 (“Judgment as a matter of law is proper when the evidence permits only one reasonable conclusion and the conclusion is contrary to that reached by the jury.”). “The causal link between a protected activity and the alleged retaliatory action ‘can be inferred from timing alone’ when there is a close proximity between the two.” See Thomas v. City of Beaverton, 379 F.3d 802, 812 (9th Cir.2004) (quoting Villiarimo v. Aloha Island Air, Inc., 281 F.3d 1054, 1065 (9th Cir.2002)). In this case, Brown reported Scott’s journal to Fuller approximately one month after Scott filed her BOLI complaint. This close temporal proximity was probably sufficient evidence on its own to support the jury’s conclusion that Brown was motivated by retaliatory animus when she reported Scott. See Thomas, 379 F.3d at 812 (holding that sufficient evidence of causation existed where adverse employment action occurred seven weeks after protected activity); see also Yartzoff v. Thomas, 809 F.2d 1371, 1376 (9th Cir.1987) (three month time lapse between protected conduct and alleged retaliatory act provided sufficient evidence of causal connection). In addition, Brown admitted at trial that Scott’s BOLI complaint surprised and upset her, and that she took Scott’s allegations personally. Also, Brown was asked to look for other material from Scott, but, before she finished doing so, she reported Scott to Fuller based on the journal alone. These combined facts provided sufficient evidence — albeit, I concede, not with much room to spare — from which a reasonable jury could have concluded that Brown’s decision to report Scott and thereby set in motion the chain of events that led to Scott’s termination was motivated by retaliatory animus, not just routine practice.
Moreover, the majority is wrong if it is suggesting that the fact that Brown’s action in bringing the journal to Fuller’s attention occurred while “Brown was engaged in activities typical and appropriate for her position,” Maj. Op. at 805, precludes the jury’s verdict that she nonetheless acted with a retaliatory motive. Supervisors have the power to retaliate precisely because their responsibilities include the authority to take steps that will foreseeably harm their subordinates’ employment circumstances. If we absolve supervisors from liability for First Amendment violations whenever they take actions while engaged into their normal responsibilities, then they will almost never be liable, even if the motive for an action challenged was retaliatory.
Here, the jury necessarily found that at least one substantial reason Brown brought the journal to Fuller’s attention was that she was angry about the BOLI charge, and, as I have shown, that factual conclusion, although quite debatable, is supported by adequate evidence. That bringing work infractions to Fuller’s attention was part of Brown’s job does not negate the finding as a matter of law, any more than a supervisor with the responsibility to hire and fire for rule infractions would be absolved of liability as a matter of law if he fires a subordinate who en*814gages in speech in part because of that speech.
Because a reasonable jury could have found that Brown acted with a retaliatory motive when she brought Scott’s journal to Fuller’s attention, and because that act was a substantial and foreseeable link in the causal chain that led to Scott’s termination, I cannot agree with the majority that Scott failed, as a matter of law, to show that her protected activity was “a substantial or motivating factor” in her termination.
It is possible that rather than concluding that Brown did not act with a retaliatory intent when she reported Scott to Fuller, the majority is instead holding that, even if Brown acted with a retaliatory motive, Fuller’s independent investigation and termination decision absolved Brown of any liability as a matter of law. If so, the majority’s holding is in tension with Gil-brook.
In Gilbrook, the plaintiffs-employees sued both their subordinate supervisors and the superior who made the ultimate decision to terminate. Gilbrook, 177 F.3d at 852-53. The jury concluded that “the plaintiffs’ protected conduct had played a ‘substantial or motivating’ role in [the subordinate supervisor’s] actions against plaintiff, but had not played such a role in the actions of [the superior who made the final decision to terminate].” Id. at 853. Despite the fact that the jury absolved the final decision-maker of liability — presumably because he made an independent decision to terminate — the court upheld the verdict against the subordinate supervisors. Id. at 855-56. In other words, the fact that the final decision maker acted independently and without a retaliatory motive did not automatically negate the subordinate supervisors’ liability for the employees’ termination. In fact, the court expressly rejected the argument, made by the subordinate supervisors, that the superior’s “legitimate, nonretaliatory motive ‘cuts off the liability of his subordinates” as a matter of law. Gilbrook, 177 F.3d at 853.
B. Brown’s Affirmative Defense
Because I would hold that Scott presented sufficient evidence from which a jury could have concluded that her protected conduct was a “substantial or motivating factor” in her termination, I would reach the question whether Brown established the affirmative defense outlined in Mt. Healthy. That defense required Brown to demonstrate, by a preponderance of the evidence, that “the disciplinary action would have been taken against [Scott] even in the absence of the protected conduct.” Gilbrook, 177 F.3d at 855 (citing Mt. Healthy, 429 U.S. at 287, 97 S.Ct. 568); see also Ostad, 327 F.3d at 883 (holding a subordinate supervisor liable where the supervisor instigated an investigation, participated actively in that investigation, and failed to prove that the employee “would have been terminated ... even in the absence of his protected speech”).4
Brown met that burden here. She introduced evidence that the journal initially was uncovered through an unrelated investigation, instigated by Fuller, of another employee; that Brown herself did not discover the journal; that employees in the human resources department were independently aware of the journal; and that the journal, by virtue of its length and inflammatory content, was likely to attract attention from HR employees and to war*815rant a report to senior management. Given that evidence, I would hold that a reasonable jury could only have concluded that Fuller would have learned of the journal, instigated the investigation of Scott and reached the same conclusion even without prompting from Brown, and therefore Scott’s termination would have occurred “even in the absence of the protected conduct.” See Gilbrook, 177 F.3d at 855.
In sum, I would reverse the jury’s verdict under part two, not part one, of the Mt. Healthy burden-shifting framework on the grounds that, based on the facts presented, Fuller’s investigation — and hence Scott’s termination — was inevitable. Such a holding acknowledges the deference we must afford to a reasonable decision by a jury, and avoids placing too great an evi-dentiary burden on a plaintiff seeking to vindicate her First Amendment rights.
For all these reasons, I concur in the judgment, but not in the majority opinion.
. On page 806, the majority states that a supervisor must have a "significant” influence on a superior's investigation in order for that investigation to have been impermissibly tainted. Maj. Op. at 806. In the next sentence, it quotes a passage from Poland in which the court noted that the supervisor in that case had “had a pervasive influence on the administrative inquiry that led to the adverse employment action.” Id. I do not read *812the majority’s reference to the quoted passage as suggesting that an employee must show that the supervisor had a "pervasive,” rather than just a "significant,” influence on the superior's investigation. The Poland court's conclusion about the high level of the supervisor's influence was merely a statement about the facts in that case, not a statement of the standard an employee is required to meet. Every time Poland states the generally applicable standard, it excludes the term "pervasive.” See, e.g., Poland, 494 F.3d at 1184 ("In summary, we hold that ... the plaintiff must show that the allegedly independent adverse employment decision was not actually independent because the biased subordinate influenced or was involved in the decision or the investigation leading thereto.”)
. The majority’s view on this point is not clear. On pages 804 and 805, the majority may be suggesting that a biased supervisor who initiates a disciplinary process for retaliatory reasons is not necessarily liable for a constitutional tort. But the passage refers to a supervisor who acts "while performing her normal supervisory responsibilities,” thus indicating that the hypothetical supervisor, although generally biased, was acting without a retaliatory motive in instigating the investigation; otherwise she would not have been simply carrying out "her normal supervisory responsibilities.”
. This causation principle is directly analogous to the "intervening force” concept in basic tort law, and differs critically from the principles that underlie vicarious liability in tort law. An "intervening force” is one which "actively operates in producing harm to another after the [defendant's] negligent act or omission has been committed.” See Restatement (Second) of Torts § 441. Despite the presence of an "intervening force” — in this case, Fuller's investigation and decision to terminate — the defendant remains liable to the plaintiff if the defendant "reasonably could have anticipated or foreseen the intervening acts and its consequences." See 3 Stuart Speiser, Charles Krause, & Alfred Gans, The American Law of Torts § 11:9 (1986); Restatement (Second) of Torts § 442A.
. The majority performs this analysis, see Maj. Op. at 807-08, but does not acknowledge it as part of Brown's affirmative defense.