Hello, new guy here and as a history buff I had a couple things to add...

MacArthur should have been court martialed even before 1941, in 1932. At that time he was Army Chief of Staff and was in charge of troops in Washington DC during the Bonus Army March. That was out of work WWI vets seeking an early payment of their Army bonus. When violence erupted in their shanty town, MacArthur went in and started forcing people out. President Hoover sent direct word twice to MacArthur not to go into the camps. However, he defied orders and continuted until all vets were driven out. Hoover was furious, but decided court martial would just make a bad situation worse.

CONELRAD was actually used four times: once each year in 1956, 1959, 1960, 1961. These were during yearly nationwide Civil Defense drills called Operation Alert, where the public would be given a specific week that a mock attack was coming, but the exact time was unknown until a sealed envelope was opened by the head of CD and he activated CONELRAD just like it was a real attack. All FM, TV, and Hams had to turn off for 15 min in 1956, and 30 min in 1959-61. In the 1956 test music by the Air Force Band was played, in the others PSA messages and live announcements from government officials were used.

The original plan with CONELRAD was that key stations in each major city would broadcast on low power on 640 or 1240 for two minutes at a time and then shut off their transmitter until signaled to turn on again. The idea was that Russian bombers would use radio direction finding equipment to find their city targets, and cycling for two minutes at a time wasn't long enough to lock in. So, instead they would have to use visual approach and hopefully get lost. The original purpose was not to inform the public, but to thwart an attack.

The 1956 test caused several stations to experience transmitter failure from the cycling. Also, people in rural areas couldn't pick up anything. The 1959-61 tests allowed key stations to broadcast continuously at higher power.