California’s San Mateo County conducted its 2015 election as an all-mail ballot election under a pilot program that previously authorized a more rural county, Yolo County, to do the same. The program authorizes San Mateo and Yolo counties to conduct three elections, other than the 2016 presidential election, by mail. They must report back to the state on costs, voter diversity, and voter turnout. According to the San Jose Mercury News and The Daily Journal, voter turnout in San Mateo increased to about 29% in 2015 from about 25% in 2013, the last comparable election.
Under all-mail ballot elections, also called “vote-by-mail” elections, every registered voter automatically receives a ballot in the mail. The voter marks the ballot, puts it in a secrecy envelope and then a separate mailing envelope, signs an affidavit on the mailing envelope’s exterior, and returns the ballot via mail or in person to a designated location.
Proponents of vote-by-mail elections say that they increase efficiency, lower costs associated with hiring poll workers, and increase voter turnout. Opponents, on the other hand, say that they increase the chances for voter fraud, have a minimal impact on voter turnout, and increase costs associated with printing and mailing ballots.
According to the National Conference of State Legislature, three states (Colorado, Oregon, and Washington) conduct their elections entirely by mail. At least 19 others authorize vote-by-mail elections for certain jurisdictions or types of elections (e.g., county elections and referenda).