It's been a few years since I had U.S. History, but I think it was a combination of America having a drinking problem since colonial times, religious pressure, and a women's movement against abusive, alcoholic husbands. People in America thought there were too many drunk, non-productive members of society and decided to do something about it. And they didn't sit about arguing over it. Many went right into bars to encourage temperance. One memorable temperance movement figure, Carrie Nation, went into saloons and destroyed liquor bottles with her hatchet. What a way to spread the message, right?