War has been a recurring tragedy in human history, begun by leaders and finished by citizens at terrible cost in human lives, and Americans are urged to remember the sacrifices that secured the freedoms of today. The Revolutionary War, fought from April 19, 1775, to September 3, 1783, brought independence after British abuses of colonial rights and liberties and gave birth to a new nation. The War of 1812, fought for U.S. maritime rights despite strong regional opposition, encouraged expansion, increased patriotism and unity, and marked strides toward cultural, political, and economic independence. The Mexican War expanded the United States from the Atlantic to the Pacific, created most or all of six new Southwestern states, gave the nation a direct stake in Asian affairs, and intensified the slavery debate that helped set in motion events leading to the Civil War. The Civil War tested the young nation, turned brother against brother, destroyed families and friendships, and became a turning point on which the survival of a unified nation, majority rule, and liberty and equality depended. The Spanish-American War and the Philippines War made the United States a world power, removed Spain from the Western Hemisphere, freed Cuba, drew the nation into colonial power politics and a controversial war in the Philippines, and permanently altered American foreign policy. In World War I, after Germany attacked and sank United States merchant and unarmed passenger ships, American intervention lifted Allied morale, strengthened battered armies, and helped advance self-determination in Europe. In World War II, after the attack on Pearl Harbor, the country united against the Axis powers, sending American men, women, and machines across the world in an effort and sacrifice said to have changed the course of world history. In the Korean War, the United States led a United Nations force after North Korea attacked South Korea, pushing Communist aggression back across the 38th Parallel and helping South Korea develop a stable nation. The Vietnam War divided American society, as the United States sought to stem communism in Asia; although politically controversial, American service members fought with heroism and determination under very difficult circumstances. Since 1945, military actions have included peacekeeping, advising and defending allies, maintaining freedom of the seas, rescuing hostages, evacuating American citizens, averting full-scale war, and thwarting terrorism, with many actions through 1989 part of the Cold War and later efforts largely dedicated to peacekeeping. Throughout these conflicts, the dead and wounded included both combat-related and non-hostile losses, and the guiding message remains that freedom is not free.