(CNN) Eric Trump may have broken the law Tuesday after he tweeted a picture of what appears to be his own ballot with a vote for his father. Then he broke social media code by deleting his tweet of the ballot picture.

"It is an incredible honor to vote for my father! He will do such a great job for the U.S.A! #MakeAmericaGreatAgain," Eric Trump wrote Tuesday morning in the tweet, with an apparent image of his ballot, which was later taken down.

New York state law makes it a misdemeanor for one person to show their completed ballot to another person -- although the law, which dates to the late 1800s, does not account for Twitter or any other social media.

The Trump campaign did not immediately respond to a request for comment.

"Although it's more than a little ironic that someone as supposedly well-informed as Eric Trump doesn't know what the laws are when it comes to ballot selfies, it's also an important reminder of just how antiquated these laws are — and how much they vary from one state to the next," said Steve Vladeck, a CNN contributor and professor of law at the University of Texas School of Law.