Not directly, of course, but by putting obstacles in the way, such as demanding state issued picture ID, & refusing to accept students' college ID, or people's picture ID from work as an acceptable alternative. Getting such an ID can present a problem for elderly people or naturalized citizens who were born in other countries--for that matter, a lot of people will have trouble taking time off work to get ID. Another way is cutting down on the number of polling places & the hours the polls are open, & refusing to allow voting by mail. There are a lot of other petty obstacles that are being thrown up in the name of preventing voter fraud (which, by the way, is a completely spurious concern) that are deliberately designed to create enough difficulty & hardship that certain classes of voters, ie, the elderly, minorities, & college age adults, that it either discourages people from voting, or prevents them from being able to vote.