[3] Horowitz recounted his ideological journey in a series of retrospective books, culminating with his 1996 memoir Radical Son: A Generational Odyssey.

[4] During years of labor organizing and the Great Depression, Phil and Blanche Horowitz were long-standing members of the American Communist Party and strong supporters of Joseph Stalin.

[8] After completing his graduate degree, Horowitz lived in London during the mid 1960s and worked for the Bertrand Russell Peace Foundation.

They included Isaac Deutscher, Jean-Paul Sartre, Stokely Carmichael, Simone de Beauvoir, Vladimir Dedijer and James Baldwin.

In January 1968, Horowitz returned to the United States, where he became co-editor of the New Left magazine Ramparts, settling in northern California.

[10] As part of their work together, Horowitz helped raise money for, and assisted the Panthers with, the running of a school for poor children in Oakland.

[21] Defunct Newspapers Journals TV channels Websites Other Congressional caucuses Economics Gun rights Identity politics Nativist Religion Watchdog groups Youth/student groups Social media Miscellaneous Other Following this period, Horowitz rejected Marx and socialism, but kept quiet about his changing politics for nearly a decade.

In early 1985, Horowitz and Collier, who also became a political conservative, wrote an article for The Washington Post Magazine entitled "Lefties for Reagan", later retitled as "Goodbye to All That".

[27] After marching with Polish dissidents in an anti-regime protest, Horowitz spoke about his changing thoughts and why he believed that socialism could not create their future.

[28] In 1992, Horowitz and Collier founded Heterodoxy, a monthly magazine focused on exposing what it described as excessive political correctness on United States college and university campuses.

[30] In a 2001 column in Salon[31] he described his opposition to reparations for slavery, calling it racism against blacks, as it defined them only in terms of their descent from slaves.

In the same year during Black History Month, Horowitz attempted to purchase advertising space in several American university student publications to express his opposition to reparations.

He, Eli Lehrer and Andrew Jones published a pamphlet, "Political Bias in the Administrations and Faculties of 32 Elite Colleges and Universities" (2004), in which they find the ratio of Democrats to Republicans at 32 schools to be more than 10 to 1.

[38] Horowitz published an Academic Bill of Rights (ABR), which he proposes to eliminate political bias in university hiring and grading.

[40] In Pennsylvania, the House of Representatives created a special legislative committee to investigate issues of academic freedom, including whether students who hold unpopular views need more protection.

[45] Politico states that Horowitz's activities and DHFC are funded in part by Aubrey and Joyce Chernick and The Bradley Foundation.

Politico stated that during 2008–2010, "the lion's share of the $920,000 it [DHFC] provided over the past three years to Jihad Watch came from [Joyce] Chernick".

[46] Between July 2000 and February 2006 the freedom center provided a total of $43,000 in funding for 25 trips taken by Republican senators and representatives including Mike Pence, Mitch McConnell, Bob Barr, Fred Thompson and others.

[68] Horowitz wrote against US intervention in the Kosovo War, arguing that it was unnecessary and harmful to US interests,[69] but supported the interventionist foreign policy associated with the Bush Doctrine, including the 2003 invasion of Iraq.

[84][85] In 2008, while speaking at University of California, Santa Barbara (UCSB), Horowitz criticized Arab culture, saying that it was rife with antisemitism.

[86] He referred to the Palestinian keffiyeh, a traditional Arab head covering that became associated with PLO leader Yasser Arafat, as a “symbol of terrorism”.

"[89][90] In a 2011 review of anti-Islamic activists in the US, the Southern Poverty Law Center identified Horowitz as one of ten people in the United States' "Anti-Muslim Inner Circle".

[94] For example, Horowitz alleged that a University of Northern Colorado student received a failing grade on a final exam for refusing to write an essay arguing that George W. Bush is a war criminal.

[96] In another instance, Horowitz said a Pennsylvania State University biology professor showed his students the film Fahrenheit 9/11 just before the 2004 election in an attempt to influence their votes.