The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.
Democracy is actually the worse way to govern people but it's the best option we have because because man is inherently corrupt.
Ctrl+F the Constitution for democracy, or even "dem" if you feel like it. https://www.archives.gov/founding-docs/constitution-transcript