US Study Guide 2026

President Harry S. Truman authorized the use of atomic bombs on Hiroshima (August 6) and Nagasaki (August 9), 1945, to end WWII.

The spoils system, a practice where a political party, after winning an election, gives government civil service jobs to its supporters, friends, and relatives as a reward for working toward victory, is most associated with President Andrew Jackson. He famously defended the practice as a democratic reform, arguing it prevented an entrenched bureaucracy and allowed for greater public participation in government.

The Jim Crow era was the period of state and local segregation laws in the South that followed Reconstruction, legally separating Black and white Americans in public life until the Civil Rights Movement.

The Compromise of 1877 resolved the disputed 1876 presidential election by allowing Republican Rutherford B. Hayes to become president in exchange for withdrawing federal troops from the South.

The Monroe Doctrine, issued in 1823, declared that the American continents were closed to future European colonization and that the U.S. would view any European attempts to impose their systems on independent Western Hemisphere nations as a threat. While it asserted American influence, it did not claim that Western Hemisphere nations were the same as Europe's due to shared republicanism; rather, it emphasized their distinctness and right to self-determination free from European interference.

The Thirteenth Amendment, ratified in December 1865, was passed specifically to abolish slavery and involuntary servitude throughout the United States. While the Emancipation Proclamation had freed slaves in Confederate states, the 13th Amendment provided a constitutional guarantee that slavery would be permanently outlawed nationwide. It was a direct result of the Union victory in the Civil War.