No employer or his agent or a corporation shall print or authorize to be printed upon any pay envelopes any statements intended or calculated to influence the political action of his or its employees; or post or exhibit in the establishment or anywhere in or about the establishment any posters, placards, or hand bills containing any threat, notice, or information that if any particular candidate is elected or defeated work in the establishment will cease in whole or in part, or other threats expressed or implied, intended to influence the political opinions or votes of his or its employees.
Ohio Revised Code - Title XXXV Elections - Section 3599.05 Corrupt practices - employer shall not influence political opinions or votes of employees. - Ohio Attorney Resources - Ohio Laws
If there are charges brought against McDonalds, the lawyers will fight over the bolded part of the law above. Technically, McDonalds did not print it on the envelope - whether that holds up in court or legally the limited scope of the law as it was modified matches, we'll have to wait and see.