Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful invasion of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 (D-Day) with the Normandy landings. A 1,200-plane airborne assault preceded an amphibious assault involving more than 5,000 vessels. Nearly 160,000 troops crossed the English Channel on 6 June, and more than two million Allied troops were in France by the end of August.

The decision to undertake a cross-channel invasion in 1944 was taken at the Trident Conference in Washington in May 1943. General Dwight D. Eisenhower was appointed commander of Supreme Headquarters Allied Expeditionary Force, and General Bernard Montgomery was named commander of the 21st Army Group, which comprised all the land forces involved in the invasion. The coast of Normandy of northwestern France was chosen as the site of the invasion, with the Americans assigned to land at sectors codenamed Utah and Omaha, the British at Sword and Gold, and the Canadians at Juno. To meet the conditions expected on the Normandy beachhead, special technology was developed, including two artificial ports called Mulberry harbours and an array of specialised tanks nicknamed Hobart's Funnies. In the months leading up to the invasion, the Allies conducted Operation Bodyguard, a substantial military deception that used electronic and visual misinformation to mislead the Germans as to the date and location of the main Allied landings. Adolf Hitler placed Field Marshal Erwin Rommel in charge of developing fortifications all along Hitler's proclaimed Atlantic Wall in anticipation of an invasion of France.

The Allies failed to accomplish their objectives for the first day, but gained a tenuous foothold that they gradually expanded when they captured the port at Cherbourg on 26 June and the city of Caen on 21 July. A failed counterattack by German forces in response to Allied advances on 7 August left 50,000 soldiers of the German 7th Army trapped in the Falaise pocket by 19 August. The Allies launched a second invasion from the Mediterranean Sea of southern France (code-named Operation Dragoon) on 15 August, and the Liberation of Paris followed on 25 August. German forces retreated east across the Seine on 30 August 1944, marking the close of Operation Overlord.

Dwight David "Ike" Eisenhower (born David Dwight Eisenhower; ; October 14, 1890 – March 28, 1969) was an American military officer and statesman who served as the 34th president of the United States from 1953 to 1961. During World War II, he served as Supreme Commander of the Allied Expeditionary Force in Europe, and achieved the five-star rank of General of the Army. He planned and supervised the invasion of North Africa in Operation Torch in 1942–1943 and the invasion of Normandy from the Western Front in 1944–1945.

Eisenhower was born into a large family of mostly Pennsylvania Dutch ancestry in Denison, Texas, and raised in Abilene, Kansas. His family had a strong religious background, and his mother became a Jehovah's Witness. Eisenhower, however, belonged to no organized church until 1952. He graduated from West Point in 1915 and later married Mamie Doud, with whom he had two sons. During World War I, he was denied a request to serve in Europe and instead commanded a unit that trained tank crews. Following the war, he served under various generals and was promoted to the rank of brigadier general in 1941. After the United States entered World War II, Eisenhower oversaw the invasions of North Africa and Sicily before supervising the invasions of France and Germany. After the war, he served as Army Chief of Staff (1945–1948), as president of Columbia University (1948–1953) and as the first Supreme Commander of NATO (1951–1952).

In 1952, Eisenhower entered the presidential race as a Republican to block the isolationist foreign policies of Senator Robert A. Taft, who opposed NATO and wanted no foreign entanglements. Eisenhower won that election and the 1956 election in landslides, both times defeating Adlai Stevenson II. Eisenhower's main goals in office were to contain the spread of communism and reduce federal deficits. In 1953, he considered using nuclear weapons to end the Korean War, and may have threatened China with nuclear attack if an armistice was not reached quickly. China did agree and an armistice resulted which remains in effect. His New Look policy of nuclear deterrence prioritized inexpensive nuclear weapons while reducing funding for expensive Army divisions. He continued Harry S. Truman's policy of recognizing Taiwan as the legitimate government of China, and he won congressional approval of the Formosa Resolution. His administration provided major aid to help the French fight off Vietnamese Communists in the First Indochina War. After the French left, he gave strong financial support to the new state of South Vietnam. He supported regime-changing military coups in Iran and Guatemala orchestrated by his own administration. During the Suez Crisis of 1956, he condemned the Israeli, British, and French invasion of Egypt, and he forced them to withdraw. He also condemned the Soviet invasion during the Hungarian Revolution of 1956 but took no action. After the Soviet Union launched Sputnik in 1957, Eisenhower authorized the establishment of NASA, which led to the Space Race. He deployed 15,000 soldiers during the 1958 Lebanon crisis. Near the end of his term, he failed to set up a summit meeting with the Soviets when a U.S. spy plane was shot down over the Soviet Union. He approved the Bay of Pigs Invasion, which was left to John F. Kennedy to carry out.

On the domestic front, Eisenhower was a moderate conservative who continued New Deal agencies and expanded Social Security. He covertly opposed Joseph McCarthy and contributed to the end of McCarthyism by openly invoking executive privilege. He signed the Civil Rights Act of 1957 and sent Army troops to enforce federal court orders which integrated schools in Little Rock, Arkansas. His largest program was the Interstate Highway System. He promoted the establishment of strong science education via the National Defense Education Act. His two terms saw unprecedented economic prosperity except for a minor recession in 1958. In his farewell address to the nation, he expressed his concerns about the dangers of massive military spending, particularly deficit spending and government contracts to private military manufacturers, which he dubbed "the military–industrial complex". Historical evaluations of his presidency place him among the upper tier of American presidents.