America was born out of conflict, and much of the history of the United States has been punctuated by war. The United States has fought wars for independence, the preservation of its union, maritime trade rights, territorial expansion, and in opposition to tyranny, communism, and fascism. (These were the biggest battles of World War II.)

When wars are fought, of course, people die – sometimes many thousands. To determine the deadliest wars for Americans, 24/7 Wall St. reviewed data from the Department of Veterans Affairs and the Department of Defense to determine the conflicts in U.S. military history with the most Americans killed in action. (Some totals are estimates, not exact figures, and are noted as such.)

Seven of the 13 wars on our list were fought in the 20th and 21st centuries. At the start of the 20th century, and fresh off its victory over Spain in the Spanish-American War, the United States began to project power around the world. In an expression of emerging American might, President Theodore Roosevelt sent the so-called “The “Great White Fleet” – 16 new battleships – around the world, from December 1907 to February 1909.

After each conflict, the United States grew ever larger as a world power, and accompanying that expansion was a perception of additional responsibilities and obligations to be borne. That has led to long and costly land wars in Asia (including the Middle East) in recent decades, despite warnings by military and political leaders against fighting land wars on that continent. (These are 20 of the longest wars in history.)

Click here to see the deadliest wars for Americans

With renewed concerns about a possible Russian invasion of Ukraine and China’s saber-rattling over its claim on Taiwan, the U.S. might be embroiled in deadly wars again.