Please make sure your employees have sufficient time to do so. For starters, it's important that employees are able to exercise their voting rights. Secondly, at least here in Ohio, it's the law.
Ohio law requires that an employer provide all employees a reasonable amount of time off to vote on election day.
According to Ohio Revised Code 3599.06:
No employer, his officer or agent, shall discharge or threaten to discharge an elector for taking a reasonable amount of time to vote on election day.... Whoever violates this section shall be fined not less than fifty nor more than five hundred dollars.
The time off doesn't have to be paid, but companies should be wary of docking exempt employees for any time spent away from work voting.
Finally, if you’re thinking of disciplining or firing an employee who arrives late, leaves early, or takes a long lunch to exercise their right to vote … just don't. Legal or illegal, it's just a lousy thing to do.