A little history detour, for those interested. I have to nitpick a bit, or at least add some context, to Jill Lepore's claim in the Sunday NYT that "[Henry] George is why, on Election Day, your polling place supplies you with a ballot that you mark in secret."
I know virtually nothing about Henry George, but I know about the adoption of the Australian ballot -- because I've read Alan Ware's wonderful The American Direct Primary, which tells the story of the primary as the intertwined with the adoption of the new ballot procedure. It's true that George played a part. Ware says that "The Australian Ballot appears to have been advocated first by the Philadelphia Civil Service Reform Association in 1882, and then, among others, by Henry George," citing a 1917 book about that reform.
It's possible that George was more important in the initial spread of the idea than Ware's sources and research revealed, and it is true, per Ware, that New York was an important state in the adoption of the new ballot. But as Ware explains it, the reformers were only at best half the story behind the adoption of the new system. The real driving force was...the parties. You see, the old system, in which the parties supplied the ballots pre-filled in for their own candidates, had a serious flaw; it was impossible for parties to control their nominations. That's because nothing prevented local groups from either printing up their own ballots (with their own candidates) or from taking the centrally printed ballots and altering them, replacing the party's official candidate with a local candidate who had lost out in the "official" nomination battle, or even with the other party's candidate for some offices. (Voters might not even know that they had voted for the "wrong" candidate if they didn't check their ballot carefully; it was also possible for deliberate fraud, in which someone could print up ballots that looked like the party's proper ones but had the names of the other party's candidates). All of these problems increased as the US began moving, after the Civil War, from a society based on in-person, one-on-one contacts, to large-scale mass society.
Switching from party-supplied ballots to state-provided ballots, then, had a major advantage for the parties: the government would accept whoever the party's official nominees were, and would automatically place those names on every single ballot. Which is why when reformers (including Henry George) proposed the Australian ballot, the parties for the most part saw it as a solution to their own problems, and didn't oppose it -- but did alter it to suit their own needs and preferences. If you want the details, see Ware.
The next step of the story comes when the parties, now in the possession of an official line on state-supplied official ballots, need a better way to officially nominate someone for that line, which becomes the story of the adoption of the direct primary. But once again, if you want to know more, consult Ware.