Thanks to Slate for this timely and eye-opening article about Thomas Jefferson's attitudes toward Islam and Muslims. He, like other prominent Americans at the time, actually advocated for the inclusion of Muslims into the new Republic. Jefferson even owned a Koran. If people believed that Muslims should be banned from entering the U.S. solely on their faith, show them this article and help them understand how un-American their discrimination actually is.
For another fascinating bit about the English pre-modern relationship with Muslims, check out this article about Queen Elizabeth I's alliance with Islamic rulers, and how that contributed to the rise of the British Empire, and eventually the U.S.