Does the U.S. public's support for the use of harsh interrogation and detention practices against terrorism suspects depend upon the religious identity of the alleged perpetrators? Some scholarly research indicates greater public acceptance for abridging the rights of Muslims after 9/11. This is consistent with literature suggesting that heightened perception of threat decreases popular tolerance for racial, ethnic, and religious outgroups. This study executes a survey experiment and finds respondents to be more permissive of the use of extraordinary detention practices, such as indefinite detention and denying suspects access to legal counsel and civilian criminal courts, against terror suspects identified as Muslims. Furthermore, the study reveals that respondents are significantly less likely to treat domestic, right‐wing terrorist suspects with extraordinary detention, suggesting ingroup leniency.