Complex sentence: Almost two-thirds of all states adopted some form of local option which enabled residents in political subdivisions to vote for or against local Prohibition; therefore, for a time, 38% of Americans lived in areas with Prohibition.
Split into simpler sentences: Almost two-thirds of all states adopted some form of local option which enabled residents in political subdivisions to vote for or against local Prohibition. For a time, 38% of Americans lived in areas with Prohibition.