This is coolbert:
From the Chicago Tribune Almanac today:
"In 1942. President Franklin D. Roosevelt ordered that men ages 45 to 64 register for nonmilitary duty."
Ages 45 to 64 register for NON-MILITARY duty!
Those previously  from the ages of 18 to 45 having to register for MILITARY DUTY!
But the US military during the Second World War [WW2] only conscripting [drafting] those up to the age of thirty-five  years of age.
At the start of American entry into the war General Marshall perceiving a need at the time for an army of two hundred  infantry divisions. That is about 20 million men alone merely for the army, NOT counting the army air corps, navy and marines.
The final decision being made to scale down the ambitious [overly so?] plans for a two hundred division army to a much more do-able and manageable army of one hundred  divisions.
Persons of what is normally considered to be middle-age [45-64 years old] being required to do what sort of non-military duty? I cannot say. The average life expectancy of an American male in 1942 was about sixty-eight years!
Middle-aged American males serving in the capacity of coast-watchers, air raid wardens, aircraft spotters, etc. That I assume to the case mainly. Any devoted readers to the blog have a better idea about this?