Since the country's formation following the American Revolutionary Era, the United States has been regarded by most of the outside world as a military power to be reckoned with. However, there have been some U.S.-involved conflicts where American success has not always been the rule of the day.
War of 1812
The War of 1812 lasted for two years between 1812 and 1814. It saw a series of battles between the United States and Great Britain over the issue of British violations of U.S. maritime rights. As a British colony, Canada also played an important role in the war by fighting on behalf of the British. Though the United States did not win the war in a clear-cut manner, the Treaty of Ghent was signed on December 24, 1814, restoring relations between the two warring factions. It also restored the boundaries of the United States and colonial Britain to pre-war conditions. Much of the U.S. capital of Washington, D.C. was burnt by the British during the conflict, and the young nation was shaken to its core. Nonetheless, numerous American war heroes emerged from the fighting (such as Andrew Jackson for his involvement at the Battle of New Orleans and the fight against Creeks in Alabama and Georgia). The national anthem of the United States was also inspired by the hostilities, as Francis Scott Key was inspired to pen the lyrics of "The Star-Spangled Banner" as he witnessed the Battle of Fort McHenry in the harbor of Baltimore, Maryland in September of 1814.
Powder River Indian War
The Battle of Powder River was fought on March 17th, 1876 in what is now the U.S. state of Montana. The event witnessed an embarrassing defeat for the United States, when a poorly planned attack on a Cheyenne encampment by Colonel Joseph J. Reynolds resulted in significant losses suffered by the United States at the hands of Native Americans. Though Colonel Reynolds managed to damage a sufficient amount of Native property, the Natives who fought bravely gained confidence from the warfare, and were able to consolidate their powers to resist the demands of the United States in the future years. After the war, Colonel Reynolds was highly criticized for his misguided tactics, including for leaving several U.S. soldiers on the battlefield in the face of enemy fire, and for losing a large number of horses. He was initially suspended from duty for a year, and ultimately never returned to service again. This battle occurred almost 11 years after the Powder River Expedition, wherein the United States' Federal forces fought against Cheyenne, Arapaho, and Sioux in what are now the present-day U.S. states of Montana, Nebraska, Wyoming, and South Dakota. This earlier expedition also ended without serving the U.S. Federal interest of securing a dominating presence and securing peace in the region.
Red Cloud's War
The United States lost another war to Native American forces in the Red Cloud’s War. Waged between 1866 and 1868, this conflict was fought over control of parts of the Powder River area of what is now Wyoming, between the Bighorn Mountains and Black Hills. The war was fought between the Lakota Sioux, Northern Arapaho, and Northern Cheyenne as allies on one side, and the United States on the other. At the end of the war, the victorious Lakota managed to retain legal control over the Powder River Country, as per the Treaty of Fort Laramie, which was signed on April 29th, 1868. The Lakota were guaranteed ownership of the Black Hills, and maintained their land and hunting rights in the region. However, this victory lasted for only 8 years. Then, with the end of the Great Sioux War, the Powder River Country was ultimately captured by the U.S. forces.
Formosa Expedition (Paiwan War)
Considered to be one of the greatest failures of the U.S. Navy, the Formosa Expedition (or the Paiwan War) of 1867 witnessed the retreat of U.S. forces before the U.S. target of defeating the Paiwan natives was achieved. The battle was triggered when Taiwanese Aborigines killed the American sailors of the ill-fated American merchant ship Rover after the vessel became shipwrecked off the coast of Formosa (modern day Taiwan). With a thirst for revenge, the United States Navy and Marine Corps launched an attack on the Paiwan Natives until the latter were forced to retreat and disengage from war. However, the U.S. Navy, instead of going forward with decisively defeating the natives, retreated from Formosa and sailed back home. All the while, attacks on wrecked merchant ships by Formosan natives continued unabated.
Second Samoan War
At the Second Battle of Vailele on April 1st, 1899, during the Second Samoan War (1898-1899), the combined British, American, and Samoan forces loyal to Samoan Prince Tanu, were defeated by the Samoan rebels loyal to Mata'afa Iosefo, a Paramount Chief of Samoa, at Vailele in Samoa. Subsequent skirmishes of the joint forces against the rebels also witnessed several victories for the Mataafan rebels, even though they suffered casualties far greater than their opponents. At the end of the war, as per the Tripartite Convention of 1899, Samoa was divided into an American territory and a German colony, while the British surrendered all rights on the island. The British were compensated by being given control over other Pacific Islands formerly owned by Germany.
Russian Civil War
The United States, as a participant in the Allied intervention during the Russian Civil War of 1918, was forced to withdraw its troops after being unable to achieve the target of empowering the anti-Bolshevik "White" forces to fight against "Red" Bolshevism in Russia. In the aftermath of the First World War, the Allied forces launched a multi-national expedition with the initial target to aid the Czechoslovak Legion to secure its trade position in the Russian ports, as well as to strengthen their Eastern Front. However, the Allied forces had to retreat when factors like a lack of domestic support, dilution of initial goals, and war-weariness started to turn the mission of Allied intervention into an unsuccessful one. Ultimately, the Reds defeated the Whites, and communists (in the form of the Soviet Union) would remain in power in Russia from that time on into the early 1990s. The Soviets would also be a major rival to the United States on the global scene for the duration of the Union of Soviet Socialist Republics.
The Korean War (1950-1953) can be considered as a major defeat for the United States, and a period when millions of lives were lost in the war (including many civilians). In the end, despite the fierce fighting, massive financial losses, and casualties, the issue of enmity between the close neighbors of North Korea (the Democratic People’s Republic of Korea) and South Korea (the Republic of Korea) remained largely unsolved. The Korean War was initially fueled by Russia, who provided the necessary advice and supplies to North Korea to attack its neighbor, South Korea. The forces of the United Nations, primarily contributed by the United States, intervened by supporting the threatened South Korea. China also joined the war when it became allies with North Korea. With all of the major world powers involved, a fierce battle ensued. However, the end of the battle did not witness any peaceful negotiations between North Korea and South Korea, and the initial United Nations' goal of uniting the two Korean states was never achieved. More than 6 decades later, tensions on the Korean Peninsula still threaten the security of the world as a whole.
Bay of Pigs Invasion
The United States suffered a major defeat in the not-so-distant past during the Bay of Pigs Invasion in Cuba. On April 17th, 1961, Brigade 2506, a U.S. CIA-sponsored paramilitary group, attempted to invade Cuba and overthrow the Cuban communist government headed by Fidel Castro, the famous Cuban politician and revolutionary. However, the Cuban Revolutionary Armed Forces, headed by Castro himself, severely defeated the United States' soldiers, forcing them to retreat within a period of only three days. This failure was a major embarrassment for America’s foreign policy agenda, and, after his victory, Castro emerged even more powerful, and strengthened Cuban ties with the USSR. The Soviet presence in Cuba to follow threatened to lead to nuclear holocaust, as the U.S. and Soviets alike prepared for atomic warfare in the Cuban Missile Crisis in the year to follow. For humanity's sake, luckily diplomacy won out in the end.
The Vietnam War (1955-1975) is a black-marked event in the histories of both Vietnam and the United States, and one when the latter country, after losing thousands of soldiers in the war, was effectively badly defeated and forced to retreat. The war was initially fought between the communist forces of North Vietnam, supported by the fellow-Communist states of the Soviet Union and China, and the government of South Vietnam, supported by the U.S. and several United Nations member allies. When the United States entered the war supporting the non-communist South Vietnamese government, the U.S. never expected the war to last as long as it did. Realizing the futile nature of the war, seeing the domestic disapproval of the conflict, and calculating the heavy losses likely to still be suffered by the United States if the war went on, President Richard Nixon decided to end the U.S. involvement in the war, and a ceasefire was negotiated in 1973. Two years later, South Vietnam surrendered to the Communist regime of the north, and, with the end of the war, the United States suffered a major setback in the Cold War. The North Vietnamese victors unified the country into a single communist Vietnamese state, just as it remains to be to this very day.