Answer

The Revolutionary War - 1775 to 1783

The small Continental army with the help of a rag-tag group of guerrilla fighters, which included Native American Indians and French forces, fought for 8 bloody years against the forces of His Majesty King George III of Great Britain, at that time probably the most powerful nation on earth, in order to win the freedom to govern themselves as they saw fit. The fledgling colonies lost nearly 5000 men in that conflict.

The War of 1812 - 1812 to 1815

A bloody little sequel to the Revolutionary War, once again against His Majesty George III's forces. The U.S. lost over 2000 men in this conflict.

The Mexican War - 1846 to 1848

This war was fought against neighbors to the south and their then masters, the kingdom of Spain. In two bloody years the U.S. lost over 13,000 men in battle.

The American Civil War (War Between the States) - 1861 to 1865

The Confederate States of America (southern secession states) and the Union (northern states) locked in deadly conflict for nearly five years over complicated legal and moral disagreements. The toll of this war was nearly 700,000 men. The bloodiest conflict in the history of America.

The Spanish-American War - 1898

A little tiff against Spain once again. The U.S. lost over 2000 men.

World War I - 1917 to 1918 (U.S. involvement)

The world's first truly global conflict. The U.S. entered this war to assist their allies, the United Kingdom and others, in securing the future of Europe. While the U.S. was only involved for the last year or so of the conflict, it suffered over 116,000 men lost.

World War II - 1941 to 1945 (U.S. involvement)

The most catastrophic event in the history of mankind. This war was a defining moment in the entire history of the human race. The U.S. fought in numerous entirely different and geographically distant theaters of operation: Europe, the Far East, the Near East, Africa, the South Pacific, the North Atlantic, the northern Pacific, etc. With over 16 million men in service to the U.S. in this war, there were over 400,000 men lost.

The Korean Conflict - 1950 to 1953

The U.S. and its allies attempt to prevent the communist North Korean forces, eventually aided by Red China, from conquering and subverting the peoples of the South Korea. This bloody, hard-fought "police action" cost the U.S. over 36,000 men lost.

The Vietnam Conflict - 1964 to 1973 (not counting technical assistance to the French prior to actually entering the conflict)

Another politically complicated conflict that initially involved the U.S. in an advisory role to their ally the French, who were attempting to maintain control of their colonies in Vietnam against the communist forces of North Vietnam. Eventually, the U.S. actually became involved in the conflict through treaty obligations with the Republic of Vietnam (South Vietnam). This terribly bloody anti-insurgent conflict lasted 9 horrible years and cost the U.S. nearly 60,000 men and women.

The Gulf War - 1990 to 1991

The U.S. and its allies forcefully and rapidly come to the aid of the country of Kuwait after it was invaded by the forces of Iraq under the leadership of Saddam Hussein. Following through on United Nations' mandates, the U.S. and its allies decimate the forces of Iraq and successfully liberate Kuwait. The U.S. lost 382 men in this conflict.

The Iraq War - 2003 to present

This conflict is so current right now, and with all the political complications and questions, suffice to say that so far the U.S. has lost over 2000 men in this war.

Add up all those men and women who've died in these wars and conflicts over the last 231 years along with the covert and overt operations such as; Grenada, Panama, Mogadishu, and the Balkans you end up with a tally of nearly 1,346,000+ men and women who've given their lives to protect the freedoms and interests of United States of America.