Vote early and vote often is considered a tongue in cheek phrase used in relation to elections. Though rarely considered as a serious suggestion, the phrase theoretically encourages corrupt electoral activity, but is used mostly to suggest the occurrence of such corruption.
The phrase had origins in the mid-19th century in the United States, but did not find widespread use until the early 1900s, when it was used in relation to activities of organized crime figures in Chicago.
The "vote early" portion suggests a person should vote early in the day and is meant to encourage voting early on election, not to encourage early balloting (which did not exist when the phrase was coined). It is often believed that early reporting of the success of one party will motivate their supporters to come out and discourage opposition.
The democratic process is based on the one voter-one vote system. The suggestion of voting often (on one day) would suggest that the person in question is voting as more than one person, suggesting the person is engaged in ballot stuffing or some other voter fraud involving an individual casting multiple ballots.
Source:
https://en.wikipedia.org/wiki/Vote_early_and_vote_often
