He signed some of the nastiest bits of American Legislation ever

The Alien and Sedition Act of 1798 "increased the residency requirement for American citizenship from five to fourteen years, authorized the president to imprison or deport aliens considered to be 'dangerous to the peace and safety of the United States,' and restricted speech critical of the government," according to the Library of Congress. The Democratic-Republican Party was intended to be silenced and undermined by these laws. The Democratic-Republican win in the 1800 elections was aided by opposition to the Sedition and Alien Acts.

Even though his detractors feared he would, Adams never deported anyone in accordance with the law. Nevertheless, many people were charged under the legislation for expressing opinions that were unfavorable of the president and the administration. Among them was James Callender, who criticized Adams in several works (these became his book The Prospect Before Us). He referred to Adams as a vile hypocrite and a "repulsive pedant." In 1800 and 1801, the Sedition Act as well as the Alien Friends Act came to an end.