>2) I said missiles bc that's what got built, but the origins of the idea predate them. The most likely implementation (at the time) would have been, as you sai

>2) I said missiles bc that's what got built, but the origins of the idea predate them. The most likely implementation (at the time) would have been, as you said, against aerial bombers, and actually based on a Battle of Britain style/ Nazi-derived rocket drone, but manually remote controlled via joystick and analog TV, and air launched from a hybrid interceptor/bomber. It could similarly be used in a bombing role with drones hitting ground targets. Interesting. So a V1-style drone used to send up "fizzle" bombs to destroy incoming bomber fleets carrying atomic weapons, Safeguard-style. (I don't see the point of calling them "fizzle" bombs, or distinguishing "pre-detonation"; even a fizzle is more than enough to take out any nearby aircraft, whether they are carrying atomic weapons or not.) I still suspect that Johnson was talking about a fission primary: * The 1949 timing strongly points toward the ongoing hydrogen weapon program that Johnson would be aware of, and not a theoretical air-defense system using yet-undeveloped drone cruise missiles carrying atomic weapons. The fission primary is something that a layman might very well refer to as "pre-detonation". * In 1949 atomic weapons (let alone any theoretical hydrogen weapon), intentional "fizzlers" or not, were still so heavy that special B29 SILVERPLATE aircraft were needed to carry them, and the US was designing a new series of ever-larger high-altitude bombers to penetrate enemy airspace. I am very skeptical that any back-of-the-envelope work at Los Alamos or Oak Ridge on bombs small enough for a V1-like drone AA cruise missile would be something that a Senator would hear about and think notable enough to mention on the air. Remember, WW2 had semi-conclusively refuted the prewar "the bomber will always get through" maxim; I am aware of no serious thinking/planning in 1949 for defending against atomic attack other than, as I said, AA and fighter squadrons, because there was no prospect of any atomic attack other than via bombers. The US maintained squadrons of interceptor aircraft on 24-hour standby around the country well after both sides deployed ICBMs and SLBMs.