Antisemitism means people treating other people badly because of their religion or culture. Some people in the United States have had bad feelings towards Jewish people throughout history. Here's a short story about the history of antisemitism in the United States:
Jewish people came to the United States in the early 1600s, but they weren't treated well. In the 1800s, Americans were afraid of Jewish people because they thought Jews would take over their jobs and their religion. Some newspapers even blamed Jews for bad things happening in their cities.
During World War II, a horrible event called the Holocaust happened. The Nazis, a group from Germany, killed millions of Jewish people because they believed Jews were not as good as other people. Many people in the United States were shocked and angry about what happened.
After the Holocaust, Jewish people in the United States were treated better because Americans had more sympathy and understanding towards them. However, antisemitism still happens today. Sometimes people blame Jews for things that happen in the world, or they say mean things about them. It's important for us to treat everyone with kindness and respect, no matter what their religion or culture is.