In the U.S., many activities of foreigners or American citizens, which, prior to 9/11, would be viewed innocently (or as just eccentric), are now viewed with suspicion, especially in regards to the behavior of anyone who looks "Arab" in terms of clothing or skin color. Six Muslim imams were removed from a U.S. airliner when they prayed before the flight and showed "suspicious behavior". Various government agencies and police forces in the U.S. have asked people to watch people around them and report "unusual" behavior, and signs posted in all public places request citizens to report anything out of the ordinary. The United States Department of Homeland Security has advised citizens to "be vigilant, take notice of your surroundings, and report suspicious items or activities to local authorities immediately."
 Discriminatory backlash
Since the September 11 attacks, Arab, Muslim, Sikh, and South-Asian Americans – as well as those perceived to be members of these groups – have been victims of threats, vandalism and arson in the United States.
 Department of Homeland Security
The United States government created the Department of Homeland Security (DHS) in response to the September 11 attacks. DHS is a cabinet-level department of the federal government of the United States charged with protecting the territory of the United States from terrorist attacks and responding to natural disasters.
With approximately 184,000 employees, DHS is the third-largest cabinet department in the U.S. federal government, after the Department of Defense and the Department of Veterans Affairs. Homeland security policy is coordinated at the White House by the Homeland Security Council. Other agencies with significant homeland security responsibilities include the Department of Health and Human Services, the Department of Justice, and the Department of Energy.
The attacks lead to significant and widespread changes in U.S. politics and foreign policy. Domestically, both parties rallied around President George W. Bush after the attacks, passing the PATRIOT Act and supporting the War in Afghanistan.
We also must never forget the most vivid events of recent history. On September the 11th, 2001, America felt its vulnerability – even to threats that gather on the other side of the earth. We resolved then, and we are resolved today, to confront every threat, from any source, that could bring sudden terror and suffering to America.
— George W. Bush, President Bush Outlines Iraqi Threat, Cincinnati, Ohio, October 7, 2002
 Societal consequences
Films and television programs produced before 2001 that feature the Twin Towers of the World Trade Center or events similar to 9/11 have been edited in re-airings on television. One such example is an episode of The Simpsons, "The City of New York vs. Homer Simpson," the main setting of which is the World Trade Center.
After 9/11, Clear Channel Communications (an owner of over 1,000 radio stations in the U.S.) released a list of songs deemed "inappropriate". The songs were not banned outright, but stations were advised not to play them.
The New York-based band Dream Theater released a live album titled "Live Scenes from New York" on September 11, 2001. The cover art depicted the Manhattan skyline, including the World Trade Center towers in flames. It was immediately recalled, and the artwork altered.
British band Bush were forced to change the name of their single 'Speed Kills' to The People That We Love. They also changed the original artwork for their album Golden State before it was released which originally depicted a picture of a plane in mid-air.
The music video for a song called 'Piece By Piece' by British band Feeder was also changed. The original video depicted animated characters of the band playing in a New York skyscraper with the world trade center in the background and planes flying near by. The band later jump from the window of the building.
- "Poll: Suspicion of Arabs, Arab-Americans deepen". USA Today. September 16, 2001. http://www.usatoday.com/news/nation/2001/09/16/poll-arab-americans.htm.
- Muslims pulled from flight may sue passengers – News – MSNBC.com
- DHS | Report Incidents
- Civil Rights Division National Origin Working Group Initiative to Combat Post-Terrorism Discrimination
- "CNN Poll: U.S. opposition to Afghanistan war remains high". CNN. http://afghanistan.blogs.cnn.com/2011/01/03/cnn-poll-u-s-opposition-to-afghanistan-war-remains-high/.
- President Bush Outlines Iraqi Threat
- Gardner, Daniel (2008). The Science of Fear: Why We Fear the Things We Shouldn't—and Put Ourselves in Greater Danger. Dutton Adult. p. 3. ISBN 0-525-95062-1. http://www.amazon.com/Science-Fear-Shouldnt-Ourselves-Greater/dp/0525950621#reader_0525950621.
- Oakley, Bill (2006). The Simpsons season 9 DVD commentary for the episode "The City of New York vs. Homer Simpson" (DVD). 20th Century Fox.
- Weinstein, Josh (2006). The Simpsons season 9 DVD commentary for the episode "The City of New York vs. Homer Simpson" (DVD). 20th Century Fox.
- http://www.snopes.com/rumors/radio.htm Urban Legends Reference Pages: Radio, Radio. Published September 18, 2001. Accessed February 10, 2008.