Anti-Semitism (or antisemitism) is discrimination or hatred of Jews.
Origins of Anti-Semitism
The first Christians were Jews, as Jesus Christ was. The story of Jesus was remembered and retold in the synagogues. Splits appeared very soon after the death of Jesus between the Pharisees and the Revisionist Jews. The Gospel of John was written quite soon after he and other revisionist Jews were barred from the synagogue by the Orthodox party. The references to Jews in the Gospel according to St John does not refer to Jews as a whole, but to the Pharisees. However, this was not well understood by later readers, and once the early generations of Jews had died out John's gospel was often used to justify acts of anti-Semitism.
One of the oldest instances of anti-Semitic claims was made in the first century AD by Apion who claimed Jews sacrificed Greeks in their temple in a ritual known as a blood libel. Christianity later brought this up again in England in 1144, after William of Norwich was found murdered. William was called a martyr and created a second wave of anti-semitism, this time in Europe. It was mostly popularized with the story of Little Saint Hugh of Lincoln, and was even present in the Canterbury Tales. This continued on for many centuries until modern times. This "blood libel" accusation has survived the centuries and is today seen in Muslim anti-Semitic propaganda.
Anti-semitism was rife in Europe well into the twentieth century. Anti-semitic references were common in the popular literature of both the 19th and early 20th centuries. In Russia, pogroms (mass slaughter) were carried out against the Jews. When Adolf Hitler needed a scapegoat on which to blame the inflationary problems of Germany, he built on a bedrock of anti-Semitism that was already there. The consequence was the Holocaust, called by Hitler the final solution to the 'Jewish problem'.
WWII to the Gulf War
Henry Ford was an outspoken anti-semite who used his newspaper, The Dearborn Independent, to reprint the false Protocols of the Elders of Zion. He was an admirer of Adolf Hitler and strongly opposed U.S. entry into the Second World War. Aviator Charles Lindberg has also been accused of being an anti-semite. He also opposed U.S. entry into the war, though implied that if we did enter, it should be on the side of Germany. During the Gulf War of 1991 anti-Semites alleged the US was being used to fight Israel's wars.
In 1984 Democratic Presidential candidate Jesse Jackson is said to have uttered anti-Semitic comments to reporter for the Washington Post when discussing the state of African-American and Jewish relations, which had been a key New Deal coalition for half a century. Jackson is reported to have referred to Jews as "Hymie's", and to New York City as "Hymietown". Jackson is alleged to have apologized for the incident.[Citation Needed]
The U.S. State Department Report on Global Anti-Semitism in 2005 said this about the current state of anti-Semitism worldwide:
- Beginning in 2000, verbal attacks directed against Jews increased while incidents of vandalism... surged. Physical assaults including beatings, stabbings and other violence against Jews in Europe increased markedly, in a number of cases resulting in serious injury and even death. Also troubling is a bias that spills over into anti-Semitism in some of the left-of-center press and among some intellectuals.
- The United States is frequently included as a target of such attacks, which often assert that U.S. foreign policy is made in Israel or that Jews control the media and financial markets in the United States and the rest of the world. ...Similarly, allegations that Jews were behind the 9/11 attacks were widely disseminated. 
In the United States, Democratic Senator Ernest Hollings was recently ostracized for public criticism of the Bush Administration  considered to be anti-Semitic.  On March 3, 2003 Rep. James Moran (D-Va.) said, "If it were not for the strong support of the Jewish community for this war with Iraq, we would not be doing this".  Some supporters of the anti-Iraq War movement have been accused of anti-Semitism, including a group known as ANSWER-Act Now to Stop War and End Racism, one of the first organizations formed to protest the policies of the Bush administration after 9/11.  
Liberal activist Cindy Sheehan, though she found popular support among leftists and the mainstream media, was condemned for her outspoken anti-Semitic conspiracy theories.  Sheehan traveled to Venezuela  to appear with Venezuelan dictator, Hugo Chavez to denounce U.S. foreign policy which she blames as responsible for the death of her son.
- Power, Ignorance, and Anti-Semitism: Henry Ford and His War on Jews http://history.hanover.edu/hhr/99/hhr99_2.html
- Asimov, Issac Isaac Asimov's Book of Facts. New York: Random House, 1977.
- Zog ate my brains, Chip Berlet, New Internationalist, October 2004.
- Report on Global Anti-Semitism, U.S. Department of State Report to the Committee on Foreign Relations and the Committee on International Relations, Released by the Bureau of Democracy, Human Rights, and Labor, January 5, 2005.
- Bush's failed Mideast policy is creating more terrorism, U.S. Senator Ernest F. Hollings, Charleston Post and Courier, 6 May 2004.
- Anti-Semitism: USA, ADL Urges Senator Hollings to Disavow Statements on Jews and the Iraq War, ADL Press Release, New York, 14 May 2004.
- Are Jews Behind the War on Iraq? A Case of Classical Anti-Semitism.
- "The 'Answer' Question Poses Difficult Choices for Liberals" by Gal Beckerman, The Forward, September 30, 2005.
- Authoritarianism and Anti-Semitism in the Anti-War Movement?. Tikkun, May/June 2003. Link is to page on the Internet Archive, archived Oct 19, 2004.
- Why Cindy Sheehan is Right!, David Duke, 8/14/2005.
- Report on Global Anti-Semitism U. S. Department of State, Bureau of Democracy, Human Rights, and Labor, January 5, 2005.