When did candidate-centered campaign advertising take off in the U.S., and what accounts for this growth?
In this paper, we analyze a novel dataset of political advertisements in newspapers between 1880 and 1930.
We show that there was a sharp increase in candidates' newspaper advertising beginning around 1910.
We also exploit the panel structure of this data to investigate the impact of political reforms on advertising.
The results suggest that the introduction of the direct primary substantially increased the number of campaign advertisements in general election races for statewide offices and for the U.S. House.
We do not find similar effects either for the Australian ballot.
Also we find little evidence that the reforms affected advertising in U.S. presidential races or by political parties.
Finally, candidates with previous office holding elected office did as much campaign advertising during this period as "new" candidates.