I was watching the movie "Atomic Cafe" a few days ago...

[Archae]

And I noticed that some politicians and commentators were seriously demanding that first Truman, and then Eisenhower use A-bombs in the Korean war.

One of the politicians was Lloyd Bentsen.
(Yup, one of us liberals!)

The fact that there never has been a nuclear weapon used in war since 1945 speaks volumes about what we all saw in Hiroshima and Nagasaki.

[Warpy]

1. Not just what we saw there

because carpet bombing had produced the same devastation, subsequent above ground testing had shown the damage fallout could do. "Downwinders" and their livestock were devastated by high fallout conditions.

The bombs don't respect national boundaries. There is no way to use them without causing high fallout damage to neighboring countries. Since this would immediately widen any war, nukes are considered a bad idea for conventional war and useful only for deterrence. This is something Pakistan and India seemed to have realized a lot faster than we did.