Why did Turnout crater at the beginning of the 20th Century?

[Tetro Kornbluth]

It is not a particularly good article and I can't vouch for its accuracy but I do think it is interesting: http://en.wikipedia.org/wiki/Voter_turnout_in_the_United_States_presidential_elections

I have to say it is full of interesting information. Notice how turnout figures in the nineteenth century often seem to correspond with turning point elections and it is interesting to consider that 1876 still records as the highest turnout in American history. I wonder to what effect various disenfranchisements had on those figures; Blacks it seems not a lot, Women (which is o/c easier to record) a lot more at least initially.

But what really caught my eye was this stretch from about 1896 to 1924:
1896         79.3%
1900         73.2%
1904         65.2%
1908         65.4%
1912         58.8%
1916         61.6%
1920         49.2%
1924         48.9%

In the Nineteenth Century turnouts into the 70s were the norm, the lowest turnout of any election between 1840 and 1900 was 71.3% in 1872 - a non-contest where one of the two major parties effectively refused to run a candidate. 1896's was relatively high for the era but that was a decisive and highly polarized election and then you see this rather steep decline. What is notable about is doesn't seem to correlate very well with 'major' elections or ones where there was a high degree of polarization and a wide range of choices (ie. Third party candidates). 1912's is well down on 1908's despite being a more of a contest in every single possible way. I suspect the incredibly low numbers for the 1920s can be explained by a combination of the implosion of the Democratic 'Ethnic' vote due to Woodrow Wilson's foreign policy, the effects of female suffrage (passed in time for 1920, many women may have been initially reluctant to vote? I'm speculating here) and the recognition that those elections were going to be massive Republican landslides. But earlier? I can't explain that plunge. I'm not an expert at all in this period of American history, so any ideas?

[Tetro Kornbluth]

Anyone?

[Tetro Kornbluth]

In the 1890s the Southern states started changing their voting laws to disenfranchise black voters, although they also ended up disenfranchising a lot of white voters as well.  Poll taxes and literacy tests were common, although threats of violence and intimidation kept many blacks from even trying to register.  When my parents registered to vote in Charleston, South Carolina in 1960 they had to read part of the state constitution and my mother still remembers it since it was filled with words she never heard of.  In some states, people could bypass the literacy test if they met property requirements or if their grandfather had been eligible to vote before the civil war (the Grandfather Clause).  Wikipedia has more information on the subject under Disfranchisement_after_the_Civil_War.  The Grandfather Clause was found unconstitutional in 1915.

Yes, but I would assume these wouldn't counted in the overall figures.

Jaichind and Ottermax, thanks... This would mean though that political mobilization in the US has more or less always excluded 40% of the population (assuming we can hold the figures of the 1910s to be the mean which is a bold assumption although it does come closest to all Post-Great Depression figures). So why is that? In most western countries turnout has cratered quite badly recently mostly thanks, I think, to Friedman's golden straight-jacket but yet turnout in the US is going up (but only because it was so low post-1968 and Watergate).