James Knox Polk was the 11th president of the United States, serving from 1845 to 1849. He previously was Speaker of the House of Representatives and Governor of Tennessee.

Zachary Taylor was an American military leader and politican who served as the 12th president of the United States from 1849 until his death in 1850. Taylor previously was a career officer in the United States Army, rose to the rank of major general and became a national hero as a result of his victories in the Mexican–American War.

Millard Fillmore was the 13th president of the United States, serving from 1850 to 1853, the last to be a member of the Whig Party while in the White House. A former member of the U.S. House of Representatives from Upstate New York, Fillmore was elected as the 12th U.S. Vice President in 1848, and succeeded to the presidency in July 1850 upon the death of U.S. President Zachary Taylor.

Franklin Pierce was the 14th president of the United States, serving from 1853 to 1857. A northern Democrat who believed that the abolitionist movement was a fundamental threat to the unity of the nation, he alienated anti-slavery groups by supporting and signing the Kansas–Nebraska Act and enforcing the Fugitive Slave Act, yet these efforts failed to stem conflict between North and South.

James Buchanan Jr. was an American lawyer and politician who served as the 15th president of the United States. He previously served as secretary of state and represented Pennsylvania in both houses of the U.S. Congress.