I lived in Washington state and Oregon, both mail in ballot states. As such both states have high voter turnout. Voters can mail in their ballots or drop them off at Libraries and other specified drop off points. It's far less expensive than opening up various polls and man powering them, and buying and/or renting machines that end up flipping your vote. Voters can fill out ballots in the comfort of their own homes over coffee. No long lines in inclement weather. No closing down polls in minority neighborhoods or moving polls at the last minute, or dealing with machines that steal your votes etc etc the way republican controlled states do during elections, such as Georgia, Texas, North Carolina and so on. Watch, blue states will be far more receptive to mail in voting, while red states will demonize mail in voting. As to voter fraud, there is virtually none. Republicans use that as a crutch to suppress voting.