How did Progressivism change the US Constitution?

During the Progressive Era, a period of significant social activism and institutional reform from the 1890s through the 1920s, political actors in the United States adopted four constitutional amendments in a short span of roughly 10 years: the Sixteenth Amendment, authorizing a direct income tax

Explanation:

four sitting presidents have been assassinated while in office but the first was abraham lincoln,

the northwest ordinance of 1787 guaranteed basic rights for settlers and banned slavery there.