Today is the 74th anniversary of the bombing of Nagasaki. Often overlooked, compared to Hiroshima, as merely the "second" atomic bomb, the Nagasaki attack is far more tricky, and important, in several ways. THREAD https://t.co/UQYoz6ftzN

First: Nagasaki wasn't, as many people know, the original target for the August 9th bombing. That was Kokura, a city somewhat to the north. Nagasaki wasn't even on the original target list — it was added to the final target order at the last minute, to replace Kyoto. https://t.co/mcAqmPOpUJ

Kokura as a target had been much more carefully studied and vetted. It was a major military arsenal surrounded by workers' houses — the kind of "ideal target" for the atomic bomb (obviously military, but also does a lot of destruction) according to the criteria of its makers. https://t.co/rV4lYEbagN

Nagasaki, by contrast, had already been bombed several times (conventionally) in WWII (most recently on August 1, 1945), was geographically unfavorable to blast effects, and was a far lower priority target in general — so low it didn't originally make the cut at all.

Why didn't Kokura get bombed? The B-29 carrying the bomb was late getting there, because it got lost in a storm, and by the time it was there the target was obscured by smoke, steam, or clouds (it's not clear, even today, which is was). https://t.co/oTlQ7zClHe

Failing to see the target visually — per their strike order — they went to the secondary target, Nagasaki. When they arrived there, they STILL couldn't see the target... but dropped it anyway. They missed the intended target by a significant amount.

(The bombardier claimed that a "hole in the clouds" opened up for him, allowing him to see the target, on the last run they made at it. Had he not dropped it, it would have had to be ditched. Luis Alvarez, the Nobel Prize physicist who helped assemble the bombs, never bought it.) https://t.co/gm9TQ3rRxk

As a result, the bomb exploded over an entirely civilian area of north-western Nagasaki. The USAAF's own map of the damage makes it clear that the primary areas hit were filled with nothing but houses, schools, churches, and prisons. Ugh. https://t.co/DXiXef2xrC

On the fringes of the blast damage were two factories, at the north and south end of it. The Army later tried to claim that dropping it in between the two was intentional — it wasn't, this was an after-the-fact justification. The actual target was more to the south.

The Army covered up the fact that the Nagasaki mission went wrong in many ways — compared to Hiroshima, it was tactically full of mishaps. They also put out the idea that Nagasaki was a super important target, and not a low-priority one added in haste.

Anyway. Why even have a second bomb, only 3 days after the first? Most people don't realize that this entire schedule was set by the weather. Originally the plan was to have a week between the bombings, to give the Japanese time to react.

Forecasts of bad weather pushed the Hiroshima date forward, and similarly pushed Nagasaki back, removing that interval. As a result, the Japanese high command were only just getting hearing of the reality of Hiroshima (they sent scientists) when the 2nd bombing mission started.

The decision to drop the second bomb when it was dropped was not made by Truman, Stimson, or even Groves — it was made on the island of Tinian, by lower-level people. It was not part of a grand strategy, contrary to popular opinion. https://t.co/Ffxf8eNmH5

In fact, archival evidence points to Truman not knowing it was going to happen. He had seen the strike order that gave the Army incredible leeway in terms of using more bombs after the first. But at Potsdam, when he asked the "schedule," he was shown this telegram: https://t.co/p4OFg9v1Cr

It says that the first bomb "of tested type" should be ready by 6 August, and the second one around 24 August. A big interval... if you don't realize that there was another bomb, the "untested type" that was dropped on Hiroshima.

Truman was pretty removed from the atomic bomb work. He also had a lot on his plate at Potsdam. He got totally fixated on the Trinity test, and I don't think he realized there were going to be two bombs ready in early August. All planning discussions were about the first use.

(Truman's personal role in the bomb decision, per General Groves, was "one of noninterference—basically, a decision not to upset the existing plans." He was told many of the plans, but it's not clear he totally understood them, or the details. Again, he had a lot on his plate.)

(The idea that Truman "decided" to use the bombs is an after-the-fact story that Truman and others liked to tell, to make the use of the bombs seem more deliberated over than it was. Many other people made decisions, but Truman himself participated in very few of them.)

Separately, most Japanese archival evidence shows that the Nagasaki bombing did not materially have an effect on the Japanese high command, either. They learned about it during a meeting they were having to discuss Hiroshima and the Soviet invasion.

This was the same meeting where they decided to put forward an offer of conditional surrender (which the US rejected). There isn't any evidence that the Nagasaki attack changed anyone's point of view in that room.

Absence of evidence is not absence of effect, but it clearly wasn't a crucial part of it. The idea that the Japanese didn't believe that the US had more atomic bombs is mostly untrue. If Nagasaki hadn't happened, it seems likely that little would have changed regarding surrender.

This is why many people who have studied it have found Nagasaki not that justifiable. Ted Telford, the chief US prosecutor at Nuremberg, concluded that had had "never heard a plausible justification of Nagasaki."

I think one can come up with "plausible justifications" for Hiroshima, even if they are debatable. Nagasaki is definitely a trickier moral issue, if your concern is with not slaughtering masses of civilians unnecessarily.

(If your argument is, "the Japanese [people] were evil and deserved it," then clearly the issue of plausible justification isn't an issue for you. I always get many replies to this effect.)

(I understand where they are coming from, especially from people who are from countries brutalized by the Japanese military. I don't think that justifies targeting children, as I've written on here before. But I understand it.)

Anyway, the most important consequence of Nagasaki, in my opinion, was that it greatly disturbed Truman. He had just gotten the casualty reports from Hiroshima and was already unnerved. He didn't know another bombing was going to happen so quickly. His attitude quickly soured.

The next day, he got a memo from General Groves saying they'd have another bomb ready in a week or so. Truman's reply was immediate: no further bombs were to be dropped without his express authority. He told his cabinet he couldn't bear to kill "all those kids." https://t.co/NvthB4Ymvd

Truman's reclamation of authority, and insisting that all further nuclear use orders be routed through the President (and not the military), changed the nature of US nuclear weapons going forward. He reinforced this many times in his later presidency.

In fact, he outright refused to give the military "custody" over the bombs themselves — they didn't actually *have* the nukes that were being produced in the Cold War, they were kept by the civilian Atomic Energy Commission. (He eventually gave them 9. Eisenhower changed this.) https://t.co/l7jqRFJC9c

In his later presidency, Truman always feared what would happen if you gave the military access to nukes. He thought they did not understand, as he told a number of military and AEC figures in 1948, that they were not "military weapons," but "used to wipe out women and children." https://t.co/pahh9pWrmX

So for me, the ultimate importance of Nagasaki is not that it was the "second" bomb used in combat. It is that it was — so far — the **last** bomb used in combat. And if we're very lucky, and very wise, it might stay that way. /THREAD https://t.co/T19Ls3fOm3

(NB: I realize I left off the caption for those graphs! These are from a website on "The President and the Bomb," on the history and policy of Presidential use authority, that I plan to debut by the end of the month.) https://t.co/ue7pFnFHzP

(For more background on the "custody" issue — in which the physical weapons were denied from the military in the early Cold War — see my writing here.) https://t.co/BCv9Ed6F3D

I have to run off to my own workshop now — where the Internet is unlikely to be working (sigh...) — so if you leave a lot of questions and/or angry disagreements, I won't see them until tomorrow. Just FYI! https://t.co/uAAVX46VgC