A county prosecutor was not required to disqualify herself from a criminal case merely because the defendant was overheard saying she felt like shooting the prosecutor.
State v. Iowa Dist. Court for Dubuque Cty., 2015 BL 349425 Iowa, No. 1402161, 10/23/15
The Iowa Supreme Court ruled, as many other courts have, that "threats alone are not sufficient to support a conflict of interest for a prosecutor which would require disqualification or recusal." The court intimated that to rule otherwise would not be realistic, because "[i]n an adversarial system, it is expected that a criminal defendant may hold negative views of the prosecutor."
The main reasoning, to not disqualify prosecutors who are threatened, is to avoid incentivizing threatening behavior of defendants. Defendants should not have the power to change the prosecutors through threats. The court did rule that disqualification is appropriate when there is an actual conflict, such as when the prosecutor is a witness, or has a personal interest in the case.