The United States evolved from a newly formed nation that fought for its independence from the Kingdom of Great Britain (1775–1783) to a world superpower status in the aftermath of World War II to the present.[1] As of 2021, the United States Armed Forces consists of the Army, Marine Corps, Navy, Air Force, and Space Force, all under the command of the Department of Defense, and the Coast Guard, which is controlled by the Department of Homeland Security.

In 1775, the Continental Congress established the Continental Army, the Continental Navy, and the Continental Marines. This newly formed military, fighting alongside the Kingdom of France, triumphed over the British during the war, which led to independence via the Treaty of Paris.

In 1789, the new Constitution made the U.S. president the commander-in-chief and gave Congress the authority to declare war.[2] Major conflicts involving the U.S. military include the American Indian Wars, the War of 1812, the Mexican-American War, the American Civil War, the Banana Wars, World War I, World War II, the Korean War, the Vietnam War, and the Iraq War.

The beginning of the United States military lies in civilian frontier settlers, armed for hunting and basic survival in the wilderness. These were organized into local militias for small military operations, mostly against Native American tribes but also to resist possible raids by the small military forces of neighboring European colonies. They relied on the British regular Army and Navy for any serious military operation.[3]

In major operations outside the locality involved, the militia was not employed as a fighting force. Instead, the colony asked for (and paid) volunteers, many of whom were also militia members.

In the early years of the British colonization of North America, military action in the thirteen colonies that would become the United States as the result of conflicts with Native Americans, such as in the Pequot War of 1637, King Philip’s War in 1675, the Yamasee War in 1715 and Father Rale’s War in 1722.

Beginning in 1689, the colonies became involved in a series of wars between Great Britain and France for control of North America, the most important of which were Queen Anne’s War, in which the British conquered French colony Acadia, and the final French and Indian War (1754–63) when Britain was victorious over all the French colonies in North America.

This final war was to give thousands of colonists, including Virginia Colonel George Washington, a military experience that they put to use during the American Revolutionary War. In the struggle for control of North America, the contest between Great Britain and France was the vital one, and the conflict with Spain, a declining power, was important but secondary.

This latter conflict reached its height in the “War of Jenkins Ear,” a prelude to the War of Austrian Succession, which began in 1739 and pitted the British and their American colonists against the Spanish.

READ ALSO: 10 Historical Ancient Wars Fought In Africa

In the colonies, the war involved a seesaw struggle between the Spanish in Florida and the West Indies and the English colonists in South Carolina and Georgia. Its most notable episode, however, was a British expedition mounted in Jamaica against Cartagena, the main port of the Spanish colony in Colombia. The mainland colonies furnished a regiment to participate in the assault as British Regulars under British command. The expedition ended in disaster, resulting from climate, disease, and the bungling of British commanders, and only about 600 of over 3,000 Americans who participated ever returned to their homes.

Ongoing political tensions between Great Britain and the thirteen colonies reached a crisis in 1774 when the British placed the province of Massachusetts under martial law after the Patriots protested taxes they regarded as a violation of their constitutional rights as Englishmen. When the shooting began at Lexington and Concord in April 1775, militia units from across New England rushed to Boston and bottled up the British in the city. The Continental Congress appointed George Washington as commander-in-chief of the newly created Continental Army, which was augmented throughout the war by colonial militia. In addition to the Army, Congress also created the Continental Navy and Continental Marines.

He drove the British out of Boston but in late summer of 1776, they returned to New York and nearly captured Washington’s army. Meanwhile, the revolutionaries expelled British officials from the 13 states and declared themselves an independent nation on 4 July 1776.

The British, for their part, lacked both a unified command and a clear strategy for winning. With the use of the Royal Navy, the British were able to capture coastal cities, but control of the countryside eluded them. A British sortie from Canada in 1777 ended with the disastrous surrender of a British army at Saratoga. With the coming 1777 of General von Steuben, the training and discipline along Prussian lines began, and the Continental Army began to evolve into a modern force.

France and Spain then entered the war against Great Britain as Allies of the U.S., ending its naval advantage and escalating the conflict into a world war. The Netherlands later joined France, and the British were outnumbered on land and sea in a world war, as they had no major allies apart from Indian tribes, Loyalists, and Hessians.

A shift in focus to the southern American states in 1779 resulted in a string of victories for the British, but General Nathanael Greene engaged in guerrilla warfare and prevented them from making strategic headway. The main British army was surrounded by Washington’s American and French forces at Yorktown in 1781, as the French fleet blocked a rescue by the Royal Navy. The British then sued for peace.

Long-building tensions between the Northern and Southern States over slavery suddenly reached a climax after the 1860 election of Abraham Lincoln of the new anti-slavery Republican Party as U.S. president. Southern states seceded from the U.S. and formed a separate Confederacy. Within the Confederate states, many U.S. forts with garrisons still loyal to the Union were cut off. Fighting started in 1861 when Fort Sumter was fired upon by Confederate troops and waves of patriotism swept both the North and the South.

The civil war caught both sides with weak military forces. Neither the North’s small standing army nor the South’s scattered state militias were capable of winning a civil war. Both sides raced to raise new armies—larger than any U.S. forces before—first with repeated calls for volunteers, but eventually resorting to unpopular large-scale conscription for the first time in U.S. history.

The Union Army initially sought a quick victory by trying to capture the Confederate capital at Richmond, Virginia, not far from the U.S. capital at Washington, D.C. The Confederate States Army hoped to win by getting Britain and France to intervene, or else by exhausting the North’s willingness to fight.

READ ALSO: A Look At Roles and Responsibilities of Special Advisers as Tinubu Sets to Appoint 20 Special Aids

As the fighting between the two capitals stalled, the North found more success in campaigns elsewhere, using rivers, railroads, and the seas to help move and supply their larger forces, putting a stranglehold on the South—the Anaconda Plan. The war spilled across the continent, and even to the high seas. After four years of appallingly bloody conflict, with more casualties than all other U.S. wars combined, the North’s larger population and industrial might slowly ground the South down. The resources and economy of the South were ruined, while the North’s factories and economy prospered filling government wartime contracts.

The American Civil War is sometimes called the “first modern war” due to the mobilization and destruction of the civilian base—total war—and due to many technical military innovations involving railroads, telegraphs, rifles, trench warfare, and ironclad warships with turret guns.