As someone who was alive back then, here's how I see it:
Historically speaking, the eclipse of the sun was seen as a harbinger of doom, bad luck and chaos. (There are accounts of human sacrifices being done in some cultures to end an eclipse.) At the time Reagan started the nuclear arms proliferation. Klaus is comparing the action to a total eclipse of the sun, although he's saying the hysteria here is justifiable.
As someone who was alive back then, here's how I see it: Historically speaking, the eclipse of the sun was seen as a harbinger of doom, bad luck and chaos. (There are accounts of human sacrifices being done in some cultures to end an eclipse.) At the time Reagan started the nuclear arms proliferation. Klaus is comparing the action to a total eclipse of the sun, although he's saying the hysteria here is justifiable.