Some scholars squabble about the particulars, but there is no question that democracy's roots go back at least 2,500 years to practices developed in the Greek city-state of Athens. But the adoption of a key pillar of democracy — the secret ballot — came far more recently. In England in the 1830s, disenfranchised working-class men and sympathetic members of Parliament launched the Chartist movement. The most crucial of its six objectives was universal suffrage for all men over 21, but not far behind was the secret-ballot provision. It took decades, but eventually the secret ballot became the democratic norm —...