Yes, the United States did the right thing by drawing a firm line against Japanese aggression. Japan's expansionist policies threatened regional stability and had devastating consequences for millions of people. The U.S. decision to respond with force helped bring an end to the war and ultimately saved lives. Although the decision to drop atomic bombs on Hiroshima and Nagasaki has been the subject of much debate and criticism, it can be argued that it was necessary to bring the war to a swift conclusion and prevent further loss of life. Overall, the U.S. decision to stand up to Japanese aggression played a significant role in shaping the outcome of World War II and the post-war world order.