However, as the threat diminished, the program shifted towards smaller systems designed to defeat limited or accidental launches.

Nonetheless mentioned are potential problems with paychecks and medical records, and accidental nuclear launches.

Would it simply be to defend against an accidental launch?

True, such defenses could also offer some protection against an accidental or unauthorized launch of missiles from Russia.

American leaders still have satellite warning systems to prevent accidental launches when other systems give false warnings.

But the risk of such an accidental launch is low compared to other safety hazards.

These are supposed to protect against an accidental launch of Soviet ballistic missiles or a limited attack by some other country that develops nuclear arms.

That would lessen the risks of accidental launch, and, in a crisis, give diplomats time to work.

But today for two nations at peace, keeping so many weapons on high alert may create unacceptable risks of accidental or unauthorized launch.

In 1981 and 1982 there were two accidental launches of Harpoon missiles.