* Freedom of speech and assembly. The First Amendment to the U.S. Constitution, adopted in 1791, guaranteed freedom of speech, the press, assembly, and petition. This was a major draw for people from countries where these freedoms were not protected.
* The right to bear arms. The Second Amendment to the U.S. Constitution, adopted in 1791, protected the right to keep and bear arms. This was important to many people who wanted to be able to defend themselves and their families from attack.
* The right to vote. Voting rights were gradually expanded in the United States over time, but by the late 19th century, all white male citizens over the age of 21 had the right to vote. This was a major step forward for democracy, and it made the United States a more attractive destination for immigrants.
* The pursuit of happiness. The U.S. Declaration of Independence, adopted in 1776, proclaimed that all people are entitled to "Life, Liberty and the pursuit of Happiness." This was a powerful statement, and it inspired people all over the world to dream of a better life in America.