The Continental Army was created on 14 June 1775 by the Continental Congress as a unified army for the colonies to fight Great Britain, with George Washington appointed as its commander. The army was initially led by men who had served in the British Army or colonial militias and who brought much of British military heritage with them. As the Revolutionary War progressed, French aid, resources, and military thinking influenced the new army. A number of European soldiers came on their own to help, such as Friedrich Wilhelm von Steuben, who taught the army Prussian tactics and organizational skills.

The army fought numerous pitched battles and in the South 1780-81 sometimes used the Fabian strategy and hit-and-run tactics, hitting where the enemy was weakest, to wear down the British forces. Washington led victories against the British at Trenton and Princeton, but lost a series of battles around New York City in 1776 and Philadelphia in 1777. With a decisive victory at Yorktown, and the help of the French, the Continental Army prevailed against the British. After the war, though, the Continental Army was quickly given land certificates and disbanded in a reflection of the republican distrust of standing armies. State militias became the new nation’s sole ground army, with the exception of a regiment to guard the Western Frontier and one battery of artillery guarding West Point’s arsenal.

However, because of continuing conflict with Native Americans, it was soon realized that it was necessary to field a trained standing army. The first of these, the Legion of the United States, was established in 1791 and disbanded in 1796.

19th Century

The War of 1812, the second and last American war against Britain, was less successful than the Revolution had been. An invasion of Canada failed, and U.S. troops were unable to stop the British from burning the new capital of Washington, D.C.. However, the Regular Army, under Generals Winfield Scott and Jacob Brown, proved they were professional and capable of defeating a British army in the Niagara campaign of 1814.

Two weeks after a treaty was signed, Andrew Jackson defeated the British in the Battle of New Orleans. However this had little effect; as per the treaty both sides returned to the status quo. Between 1815 and 1860, a spirit of Manifest Destiny was common in the U.S., and as settlers moved west the U.S. Army engaged in a long series of skirmishes and battles with Native Americans that the settlers uprooted. The U.S. Army also fought and won the Mexican-American War (1846-1848), which was a defining event for both countries. The U.S. victory resulted in acquisition of territory that eventually became all or parts of the states of California, Nevada, Utah, Colorado, Arizona, Wyoming and New Mexico.

The Battle of Gettysburg, the turning point of the American Civil War The Civil War was the most costly war for the U.S. in terms of casualties. After most states in the South seceded to form the Confederate States of America, CSA troops opened fire on the Union-held Fort Sumter in Charleston, South Carolina, starting the war. For the first two years Confederate forces solidly defeated the U.S. Army (with a few exceptions), but after the decisive battles of Gettysburg in the east and Vicksburg in the west, combined with superior industrial might and numbers, Union troops fought a brutal campaign through Confederate territory and forced the surrender of the Confederate Army of Northern Virginia at Appomatox Courthouse and the Confederate Army of the Carolinas at Dunham Station in April 1865.

The war remains the deadliest conflict in American history, resulting in the deaths of 620,000 soldiers. Based on 1860 census figures, 8% of all white males aged 13 to 43 died in the war, including 6% in the North and 18% in the South. Following the Civil War, the U.S. Army fought a long battle with Native Americans, who resisted U.S. expansion into the center of the continent. By the 1890s the U.S. saw itself as a potential international player. U.S. victories in the Spanish-American War and the controversial and less well known Philippine-American War, as well as U.S. intervention in Latin America and the Boxer Rebellion, gained America more land and power.

20th Century

Assault on a German bunker, France, circa 1918

Starting in 1910, the army began acquiring fixed-wing aircraft. In 1910, Mexico was having a civil war, peasant rebels fighting government soldiers. The army was deployed to American towns near the border to ensure safety to lives and property. In 1916, Pancho Villa, a major rebel leader, attacked Columbus, New Mexico, prompting a U.S. intervention in Mexico until 7 February 1917. They fought the rebels and the Mexican federal troops until 1918. The United States joined World War I in 1917 on the side of Britain, France, Russia, Italy and other allies. U.S. troops were sent to the front and were involved in the push that finally broke through the German lines. With the armistice in November 1918, the army once again decreased its forces. The U.S. joined World War II after the Japanese attack on Pearl Harbor. On the European front, U.S. Army troops formed a significant portion of the forces that captured North Africa and Sicily. On D-Day and in the subsequent liberation of Europe and defeat of Nazi Germany, millions of U.S. Army troops played a central role.

In the Pacific, army soldiers participated alongside U.S. Marines in capturing the Pacific Islands from Japanese control. Following the Axis surrenders in May (Germany) and August (Japan) of 1945, army troops were deployed to Japan and Germany to occupy the two defeated nations. Two years after World War II, the Army Air Forces separated from the army to become the United States Air Force in September 1947 after decades of attempting to separate. Also, in 1948 the army was desegregated. The end of the Second World War set the stage for the East-West confrontation known as the Cold War. With the outbreak of the Korean War, concerns over the defense of Western Europe rose. Two corps, V and VII, were reactivated under Seventh United States Army in 1950 and American strength in Europe rose from one division to four. Hundreds of thousands of U.S. troops remained stationed in West Germany, with others in Belgium, the Netherlands and the United Kingdom, until the 1990s in anticipation of a possible Soviet attack. Soldiers of the 2nd Infantry Division man a machine gun during the Korean War During the Cold War, American troops and their allies fought Communist forces in Korea and Vietnam. The Korean War began in 1950, when the Soviets walked out of a U.N. Security meeting, removing their possible veto. Under a United Nations umbrella, hundreds of thousands of U.S. troops fought to prevent the takeover of South Korea by North Korea, and later, to invade the northern nation.

After repeated advances and retreats by both sides, and the PRC Peoples Volunteer Army’s entry into the war, the Korean Armistice Agreement returned the peninsula to the status quo in 1953. The Vietnam War is often regarded as a low point for the army due to the use of drafted personnel, the unpopularity of the war with the American public, and frustrating restrictions placed on the military by American political leaders. While American forces had been stationed in the Republic of Vietnam since 1959, in intelligence & advising/training roles, they did not deploy in large numbers until 1965, after the Gulf of Tonkin Incident. American forces effectively established and maintained control of the “traditional” battlefield, however they struggled to counter the guerrilla hit and run tactics of the communist Viet Cong and the North Vietnamese Army. On a tactical level, American soldiers (and the U.S. military as a whole) did not lose a sizable battle. An infantry patrol moves up to assault the last Viet Cong position at Dak To, South Vietnam after an attempted overrun of the artillery position by the Viet Cong during Operation Hawthorne During the 1960s the Department of Defense continued to scrutinize the reserve forces and to question the number of divisions and brigades as well as the redundancy of maintaining two reserve components, the Army National Guard and the Army Reserve.

In 1967 Secretary of Defense McNamara decided that 15 combat divisions in the Army National Guard were unnecessary and cut the number to 8 divisions (1 mechanized infantry, 2 armored, and 5 infantry), but increased the number of brigades from 7 to 18 (1 airborne, 1 armored, 2 mechanized infantry, and 14 infantry). The loss of the divisions did not set well with the states. Their objections included the inadequate maneuver element mix for those that remained and the end to the practice of rotating divisional commands among the states that supported them. Under the proposal, the remaining division commanders were to reside in the state of the division base. No reduction, however, in total Army National Guard strength was to take place, which convinced the governors to accept the plan. The states reorganized their forces accordingly between 1 December 1967 and 1 May 1968. The Total Force Policy was adopted by Chief of Staff of the Army General Creighton Abrams in the aftermath of the Vietnam War and involves treating the three components of the army – the Regular Army, the Army National Guard and the Army Reserve as a single force. Believing that no U.S. president should be able to take the United States (and more specifically the U.S. Army) to war without the support of the American people, General Abrams intertwined the structure of the three components of the army in such a way as to make extended operations impossible, without the involvement of both the Army National Guard and the Army Reserve.

The 1980s was mostly a decade of reorganization. The army converted to an all-volunteer force with greater emphasis on training and technology. The Goldwater-Nichols Act of 1986 created unified combatant commands bringing the army together with the other four military services under unified, geographically organized command structures. The army also played a role in the invasions of Grenada in 1983 (Operation Urgent Fury) and Panama in 1989 (Operation Just Cause). By 1989 Germany was nearing reunification and the Cold War was coming to a close. Army leadership reacted by starting to plan for a reduction in strength. By November 1989 Pentagon briefer were laying out plans to reduce army end strength by 23%, from 750,000 to 580,000.

[15] A number of incentives such as early retirement were used. In 1990 Iraq invaded its smaller neighbor, Kuwait, and U.S. land forces, quickly deployed to assure the protection of Saudi Arabia. In January 1991 Operation Desert Storm commenced, a U.S.-led coalition which deployed over 500,000 troops, the bulk of them from U.S. Army formations, to drive out Iraqi forces. The campaign ended in total victory, as Western coalition forces routed the Iraqi Army, organized along Soviet lines, in just one hundred hours. After Desert Storm, the army did not see major combat operations for the remainder of the 1990s but did participate in a number of peacekeeping activities . In 1990 the Department of Defense issued guidance for “rebalancing” after a review of the Total Force Policy, but in 2004, Air War College scholars concluded the guidance would reverse the Total Force Policy which is an “essential ingredient to the successful application of military force.”

21st Century

U.S. Army and Iraqi Army soldiers patrol borders in Iraq, in November 2009 After the September 11 attacks, and as part of the Global War on Terror, U.S. and NATO forces invaded Afghanistan in 2001, displacing the Taliban government. The U.S. Army led the combined U.S. and allied Invasion of Afghanistan in 2001, and Iraq in 2003. In the following years the mission changed from conflict between regular militarizes to counter insurgency, resulting in the deaths of more than 4,000 U.S service members (as of March 2008) and injuries to thousands more. and 23,813 insurgents were killed in Iraq between 2003-2011. The lack of stability in the theater of operations has led to longer deployments for Regular Army as well as Reserve and Guard troops.[citation needed] The army’s chief modernization plan was the FCS program. Many systems were canceled and the remaining were swept into the BCT modernization program.[citation needed]

Army Components

The task of organizing the U.S. Army commenced in 1775. In the first one hundred years of its existence, the United States Army was maintained as a small peacetime force to man permanent forts and perform other non-wartime duties such as engineering and construction works. During times of war, the U.S. Army was augmented by the much larger United States Volunteers which were raised independently by various state governments. States also maintained full-time militias which could also be called into the service of the army.

World War II, Europe

By the twentieth century, the U.S. Army had mobilized the U.S. Volunteers on four separate occasions during each of the major wars of the nineteenth century. During World War I, the “National Army was organized to fight the conflict, replacing the concept of U.S. Volunteers. It was demobilized at the end of World War I, and was replaced by the Regular Army, the Organized Reserve Corps, and the State Militias. In the 1920s and 1930s, the “career” soldiers were known as the Regular Army” with the “Enlisted Reserve Corps” and “Officer Reserve Corps” augmented to fill vacancies when needed. In 1941, the “Army of the United States” was founded to fight World War II. The Regular Army, Army of the United States, the National Guard, and Officer/Enlisted Reserve Corps (ORC and ERC) existed simultaneously. After World War II, the ORC and ERC were combined into the United States Army Reserve. The Army of the United States was re-established for the Korean War and Vietnam War and was demobilized upon the suspension of the draft. Currently, the army is divided into the Regular Army, the Army Reserve, and the Army National Guard. The army is also divided into major branches such as Air Defense Artillery, Infantry, Aviation, Signal Corps, Corps of Engineers, and Armor. Before 1903 members of the National Guard were considered state soldiers unless federalized (i.e., activated) by the President.

Since the Militia Act of 1903 all National Guard soldiers have held dual status: as National Guardsmen under the authority of the governor of their state or territory and, when activated, as a reserve of the U.S. Army under the authority of the President. Since the adoption of the total force policy, in the aftermath of the Vietnam War, reserve component soldiers have taken a more active role in U.S. military operations. For example, Reserve and Guard units took part in the Gulf War, peacekeeping in Kosovo, Afghanistan, and the 2003 invasion of Iraq.