It's basically just in case some serious shit goes down and the president is required to make an immediate decision on an immediate event.
Like a major terrorist attack happens, or a reactor goes meltdown, an earthquake, volcanic eruption, chinese incursion into airspace, ANYTHING that might cause someone to say 'get the president on the phone now'.
They don't want any confusion over whose decision they're supposed to follow.
It's basically just in case some serious shit goes down and the president is required to make an immediate decision on an immediate event.
Like a major terrorist attack happens, or a reactor goes meltdown, an earthquake, volcanic eruption, chinese incursion into airspace, ANYTHING that might cause someone to say 'get the president on the phone now'.
They don't want any confusion over whose decision they're supposed to follow.