issues not decided here.
This brings the discussion to the issue the parties deem central to the case: whether the conceded existence of probable cause for the arrest bars recovery regardless of any intent or purpose to retaliate for past speech. Two major precedents could bear on this point, and the parties disagree on which should be applicable here. The first is this Court’s decision in Mt. Healthy City Bd. of Ed. v. Doyle, 429 U.S. 274 (1977). See also Board of Comm’rs, Wabaunsee Cty. v. Umbehr, 518 U.S. 668 (1996). Lozman urges that the rule of Mt. Healthy should control and that under it he is entitled to recover. The second is this Court’s decision in Hartman v. Moore, 547 U.S. 250 (2006), which the City cites for the proposition that once there is probable cause there can be no further claim that the arrest was retaliation for protected speech. Mt. Healthy arose in a civil, not criminal, context. A city board of education decided not to rehire an untenured school teacher after a series of incidents indicating unprofessional demeanor. 429 U.S., at 281–283. One of the incidents was a telephone call the teacher made to a local radio station to report on a new school policy. Id., at 282. Because the board of education did not suggest that the teacher violated any established policy in making the call, this Court accepted a finding by the District Court that the call was protected speech. Id., at 284. The Court went on to hold, however, that since the other incidents, standing alone, would have justified the dismissal, relief could not be granted if the board could show that the discharge would have been ordered even without reference to the protected speech. Id., at 285–287. In terms of precepts in the law of torts, the Court held that even if retaliation might have been a substantial motive for the board’s action, still there was no liability unless the alleged constitutional violation was a but-for cause of the employment termination. Ibid.; see also Umbehr, supra, at 675.
