The Office of Special Counsel has issued an advisory opinion stating that federal employees who choose to promote a Presidential candidate, for example by wearing a campaign t-shirt are not in violation of the Hatch Act.
"To clarify, after Election Day, with rare exception, activities supporting or opposing a Presidential candidate will not affect the result of the election, as the only individuals left to cast their votes are the members of the Electoral College," said the opinion, continuing, "Thus, activities like wearing campaign t-shirts or displaying the candidate’s picture, do not constitute political activity, and the Hatch Act does not prohibit a federal employee from engaging in such activities, even while on duty or in a federal room or building."
That is, until Obama comes up for re-election. Once he again becomes a candidate for public office then displaying his image — and so on — would be prohibited under the Hatch Act. OSC said it would announce when and if that occurs.
However, while it’s OK to wear an Obama or McCain t-shirt it’s not OK if the shirt also directly promotes a party. So, an Obama shirt is OK, but a "Dems for Obama" t-shirt is not OK under the Hatch Act, says OSC.
"For example, a federal employee can never wear or display a Democratic or Republican party t-shirt or similar item while on duty or in the federal workplace," said the opinion.

