The Alien and Sedition Acts were passed in 1798 by President John Adams. They made it possible for the federal government to imprison any immigrant suspected of working against the common good and also to imprison anyone who said anything bad about the government (which completely violated the First Amendment, by the way).
It remade Europe after the downfall of French Emperor Napoleon I and tried to restore old boundaries as well as resizing the main powers so they could balance each other and remain at peace.