Since the September 11 attacks, ADC attorneys have addressed hundreds of cases against airlines and employers for discrimination on the basis of ethnicity and national origin and against the United States government for discriminatory detentions of Arabs and Muslims without probable cause.

[17] Although Jewish Defense League leader Irv Rubin, who lived in Southern California, made controversial statements about the bombing,[18][19] the investigation focused on Robert Manning and his wife Rochelle who fled to Israel.

[21] ADC documented more than 100 hate crimes against Arab-Americans committed from August 1990 through March 1991, including arson against a Detroit restaurant and the planting of a bomb in a San Diego mosque.

[25] In 1993, twelve civil rights groups led by the ADC and the National Lawyers Guild filed a lawsuit in U.S. District Court in Los Angeles alleging that the Anti-Defamation League (ADL) had spied on their political activities and shared information with police.

[28] Then communications director Hussein Ibish claimed that ADL was gathering information "systematically in a program whose clear intent was to undermine civil rights and Arab-American organizations.

[32][33] One lawsuit by Arabs claiming they were targeted for deportation because of affiliations with an unpopular political group, in violation of their First and Fifth Amendment, reached the Supreme Court, in Reno v. American-Arab Anti-Discrimination Committee 525 U.S. 471 (1999).

[34] While the ruling cast doubt on the role of secret evidence,[33] many observers interpreted it as restricting First Amendment rights of all non-citizens, including legal immigrants.

[32] In 2000, ADC supported a congressional letter to President Bill Clinton, signed by 68 members of congress, calling for economic sanctions against the people of Iraq to be lifted.

ADC's press release noted that the United Nations estimated that over one million civilians, mostly children, had died from malnutrition and disease due to the embargo.

[36][better source needed] After the September 11 attacks, ADC concerned itself with "an unprecedented backlash in the form of hate crimes, discrimination and various civil liberties violations" against the Arab American community, as well as against Muslims.

[38] It was a signatory to a March 17, 2003 letter from a number of civil liberties and other organizations asking members of the U.S. Congress to oppose the leaked draft of the Domestic Security Enhancement Act of 2003 holding it contained "a multitude of new and sweeping law enforcement and intelligence gathering powers … that would severely dilute, if not undermine, many basic constitutional rights."

[40] In 2003, when then University of South Florida professor Sami Al-Arian was indicted on terrorism-related charges, then-communications director Hussein Ibish stated: "Until we have some reason based in fact to think otherwise, I think that the presumption has to be that this is a political witch-hunt, a vendetta, and a kind of very, very ugly post-9/11 McCarthyism.

"[41] In December, 2005, after Al-Arian was acquitted of eight charges, and the jury deadlocked on nine others,[42] ADC stated that in the verdict was seen as a "major defeat" for some of the most controversial elements of the Patriot Act.

[45] In 2003, ADC was a co-plaintiff with the American Civil Liberties Union and other groups in the first major legal challenge to Section 215 of the Patriot Act that expands federal agents’ power to secretly obtain records and personal belongings of citizens and permanent residents.

ADC then-communications director Hussein Ibish wrote that the extended definition trivialized the "very concept of anti-Semitism" and "smears and impugns the motives of all those who support the human and political rights of Palestinians."

A Merriam-Webster company spokesman stated that the older definition was not supported by current usage and probably would be dropped with publication of a new unabridged version by 2010.

[49] In the weeks before the 2004 United States presidential election, a San Francisco-based ADC official wrote about federal law enforcement's "October Plan," including home intrusions and work site visits on Middle Easterners and South Asians to seek information about a possible pre-election terrorist attack.

The lawsuit asked the federal court to compel the officials to request a cease fire and to stop all U.S. military support to Israel during the evacuation of US citizens from Lebanon.

[4] ADC protested a March 2008 Iowa comment on radio by Republican Congressman Steve King who said that if Barack Obama was elected president, “then the radical Islamists and their supporters will be dancing in the streets in greater numbers than they did on September 11 because they will declare victory in this War on Terror."