"The Fog of War" is a great documentary...

The Fog of War

The Fog of War: Eleven Lessons from the Life of Robert S. McNamara is a 2003 American documentary film about the life and times of former U.S. Secretary of Defense Robert McNamara, illustrating his observations of the nature of modern warfare. It was directed by Errol Morris and features an original score by Philip Glass. The title derives from the military concept of the "fog of war", which refers to the difficulty of making decisions in the midst of conflict.

[I made an edit.] McNamara talks about firebombing bombing and he quotes Curtis LeMay who said they'd be tried for war crimes had the US lost. AMWB's comment has the video.

The firebombing was horrific for civilians. The 9/10 March 1945 firebombing was clearly a terror attack. The US knew they were killing civilians not soldiers.

Emphasis mine

Bombing of Tokyo (10 March 1945)

On the night of 9/10 March 1945, the United States Army Air Forces (USAAF) conducted a devastating firebombing raid on Tokyo, the Japanese capital city. This attack was code-named Operation Meetinghouse by the USAAF and is known as the Great Tokyo Air Raid in Japan. Bombs dropped from 279 Boeing B-29 Superfortress heavy bombers burned out much of eastern Tokyo. More than 90,000 and possibly over 100,000 Japanese people were intentionally killed, mostly civilians, and one million were left homeless.

[It was] the most destructive single air attack in human history. The Japanese air and civil defenses proved largely inadequate; 14 American aircraft and 96 airmen were lost.

The death toll was possibly as large as the deaths from both the nuclear weapons dropped on Hiroshima and Nagasaki: 105,000