Baron de Montesquieu would have supported the bombing of Nagasaki. He would have supported this because he believed in the separation of powers within a government. Because the government had different branches and were separated they had to go through all of them to bomb a foreign nation.
When once a army is established, it ought not to depend immediately on the legislative but on the executive power, and this from the very nature of the thing; its business consisting more in action than in deliberation.
Montesquieu argues that a government should not solely depend on one branch but three different branches of government and the separations of power.In the case of the Atomic bomb being dropped on Nagasaki and ending the war in the pacific with the second bomb.
To prevent executive power from being able to oppress, it is requisite, that the armies, with which it is intrusted, should consist of the people, and should have the same spirit as the people.
When Baron de Montesquieu tells us that he believes in the separation of powers he would be happy that it went through all the branches of the government before they began the first and second droppings of the atomic bombs in Japan.