VA History Office Refugees crossing behind U.S. Army lines, circa 1862. Photo courtesy of the Library of Congress. The American Civil War began in April 1861 as a response to preserve the United States. Within a month, enslaved African Americans seeking shelter behind Union lines shifted the war’s objectives. Many U.S. Army leaders, such as Major General Benjamin Butler, were unwilling to return these individuals to their disloyal enslavers. Hoping to deny the Confederacy of its labor force, U.S. officials recognized these self-emancipated people and harbored them as “contraband of war.” By running away from slavery, these Black Americans helped make emancipation a strategical component of preserving the Union.