Note that 1942 is when Randolph heard the song, not when it was written. Seems to me it must come from sometime before women got the vote in the U.S. with the 19th Amendment (1920).
In the UK, women over 30 were allowed to vote beginning 1918, women over 21 beginning 1928, and women over 18 beginning 1969 - but this apprears to be a US song. The "Silver Bill" was a very controversial topic in the late 19th century. William Jennings Bryan made his famous "Cross of Gold" speech to the Democratic convention in 1896, and got the presidential nomination. I still wonder why he lost to McKinley (twice), and to Taft. Bryan was a leading advocate of the free coinage of silver.
There seemed to be a strong element of machismo on both sides of the silver bill argument.
-Joe Offer-