Answer: Voters in states with late elections knew the results of early elections.
Explanation:
Before voting day was standardized across the United States in 1845, states, as the question mentions, were allowed to vote any time they pleased within a 34-day period before the first Wednesday in December.
This had the effect of letting voters in states with late elections know the results from the states with early elections.
This was problematic because knowing the results of early voting affected the turnout in states with late voting as they either showed up in more numbers to get a person elected or in less numbers to do the same.
Congress therefore decided to standardize the voting day and this is why election day is one day which is the first Tuesday following the first Monday in November.
It is a gerund. If we added the preposition 'by' like, 'by sprinting the gazelle outran...', we'd know better that prepositions, the case with 'by' for instance, went with gerunds.
