In Clark County School District v. Breeden, 533 U.S. 268 (2001) the plaintiff alleged that she had been harassed, and that her employer had transferred her in retaliation for filing her subsequent administrative complaint and civil action. Her only evidence that her complaints were causally responsible for her transfer was that she had filed her administrative complaint two years before the transfer, and that she had received a right-to-file letter three months before the transfer. The court in Clark County School District held that this evidence did not establish the causal element of a prima facie case of retaliation, reasoning that there was no evidence that the decision maker who ordered the transfer knew of the right-to-sue letter or the administrative complaint, and even if the decision maker was aware of this complaint, the two-year gap between its filing and the transfer nullified the inference of a causal connection. (Ibid.) The U.S. Supreme Court stated that the protected activity and the employment action must be very close in time for the rule of temporal proximity to apply. ( Id. at p. 272.) In the Clark County case, employment action was taken against the employee 20 months after she filed an EEOC complaint and four months after the EEOC issued its right to sue letter. The Supreme Court held this was too lengthy a period to invoke temporal proximity. (Ibid.) Although the employment action was taken less than one month after the employee actually filed a lawsuit, this was irrelevant to ascertaining a causal connection because the parties conceded that the employer was not aware that a lawsuit had been filed until after the decision on the employment action had been made. (Ibid.)