During the late 1800s and early 1900s, the growing popularity of reform-minded third parties (such as the populist party) forced the two major parties to

During the late 1800s and early 1900s, the growing popularity of reform-minded third parties (such as the Populist Party) forced the two major parties to adopt some of the third-parties' policies.

Reform-minded third parties are parties that favor or promote reform through government actions. One of these parties is the Populist Party. The People's party, more commonly known as the Populist party, was organized in St. Louis in 1892. 

popular sovereignty   influenced the declaration of independence because the colonists wanted to have freedom to do they wanted so they put into writing