Image: E-voting paper trails, state by state

Some 27 states have laws or regulations on their books requiring paper receipts for e-voting, although that doesn't necessarily mean they have implemented them yet.

Another 12 states plus Washington, D.C., are still considering proposals. Ten have no proposal before them, and one state has a mixture of requirements.

Three states--Michigan, Missouri and Nevada--introduced voter-verified paper requirements or paper ballot requirements by executive order.

Photo by VerifiedVoting.org