Wasn't Reagan said to have been shocked by the USSR' s response and how near we had been to war and that that changed his attitude?It's not that known around, but in 1983 we have been again really near to an atom conflict between the two superpowers.
The National Security Archive [and academical organization c/o George Washington University] thanks to FOIA has obtained documents about what happened.
I quote the article
The Able Archer War Scare Declassified PFIAB Report Released
The Able Archer 83 Sourcebook]
In good substance the exercise had misinterpreted by the Russians who thought to a real war operation. Politicians minimized, but the risk was real and concrete.