Article 1, Section 8, Clause 13: The Navy

To provide and maintain a Navy;

Congress is here granted authority to create and maintain a navy.

Unlike appropriations for the Army, appropriations for the Navy  have no time limit. The Founders regarded a standing Navy as no great threat to republican government, so long as the army was firmly under civilian control, and understood that building and fitting out ships required appropriations over periods of several years.

The Constitution was written and adopted at a time when Britain still ruled the waves. Having a Navy at all was a rather bold move. During the Revolutionary War, most ships under the American flag were privateers, civilian ships whose masters had letters of marque authorizing them to seize enemy shipping on behalf of the American government. But lack of a navy had greatly hindered the American cause. During the disastrous New York campaign, the British had literally  hundreds of ships in New York Harbor or thereabouts, giving them a freedom of movement that allowed them to outflank the Americans repeatedly. (It could even be argued that this advantage was not pressed as hard as it could have been.) With this as recent history, the Founders were willing for Congress to provide as large a navy as the national budget would permit.

Nevertheless, it was not until well after the War of 1812 that the U.S. Navy was powerful enough even to be a regional naval power. The national defense relied on distance from potentially  hostile powers and on the Army, clearly the senior service throughout the early part of American history. It was not until the Civil War that the U.S. had a navy capable even of guaranteeing control of its own waters, and not until the post-World War I naval limitations treaties that the U.S. was acknowledged as the peer of the British in naval might.

Today the U.S. Navy is overwhelmingly the most powerful in the world, in contrast with an Army that is merely in the top ten. Together with the Air Force, the Navy is capable of projecting considerable power overseas — a recognition that isolation is no longer any protection, and an acknowledgement that we are the guarantors of the security of numerous smaller liberal states.