How did the battles of Iwo Jima and Okinawa change our world today?

The Battles of Iwo Jima and Okinawa are important in American history because these two islands were key Japanese fortresses and their capture made it possible to bomb Tokyo. The battles themselves took months, and the islands saw some of the bloodiest fighting of WWII. In a larger context, Japanese tenacity made American strategists reconsider their plans to end the war. Japanese kamikaze attacks and virtually no prisoners-of-war among the Japanese made it apparent that an invasion of the Japanese main island of Honshu would take months and would lead to more than one million dead Japanese. It would almost be a war of extermination on the main island. American planners coded the invasion as "X-Day" and planned it for November 1945. American scientists working on the Manhattan Project pointed to the new atomic bomb that was successfully tested in New Mexico in July 1945 because they thought it could end the war. Truman signed off on dropping an atomic bomb on Hiroshima and another on Nagasaki, thus ending the war and bringing about the Atomic Age. Without the tenacious defense of Iwo Jima and Okinawa, however, it is unlikely Truman would have decided to use such an untested and risky weapon.