What were Franklin Pierce's major accomplishments?

Franklin Pierce was the fourteenth president of the United States. He served from 1853 to 1857. Although he was liked by both the North and South during his campaign, he lost that popularity while serving in office. His biggest accomplishment was the Gadsden Purchase, in which he bought 30,000 square miles of land from Mexico for $10 million to provide a route for the Transcontinental Railroad. This land would later become southern Arizona and New Mexico.
Under his presidency, Commodore Matthew Perry signed the Treaty of Kanagawa with Japan, which opened ports for United States trading and created a United States consulate in Japan. Pierce also attempted to purchase Cuba but was unsuccessful in doing so. One of his most controversial pieces of legislation was the Kansas-Nebraska Act, which allowed both states to enter the Union without defining their slave status beforehand. This directly refuted the Missouri Compromise and was another factor that led to the Civil War.