The United States Navy

Naval power would play a significant role during the American Civil War, where the Union had a distinct advantage over the Confederacy on the seas. A Union blockade on shipping handicapped the Southern effort throughout the conflict. The two American navies would help usher in a new era in world naval history by putting ironclad warships into combat for the first time. The Battle of Hampton Roads in 1862, which pitted USS Monitor against CSS Virginia, became the first engagement between two steam-powered ironclads. Soon after the war, however, the U.S. Navy's fleet slipped into obsolescence because of neglect.
• 20th century
Our ships are our natural bulwarks.—Woodrow Wilson
A modernization program beginning in the 1880s brought the U.S. in line with the navies of countries such as Britain and Germany. In 1907, most of the Navy's battleships, with several support vessels, dubbed the Great White Fleet, were showcased in a 14-month circumnavigation of the world. Ordered by President Theodore Roosevelt, it was a mission designed to demonstrate the Navy's capability to extend to the global theater.