Apparently, this summer The New York Times standards editor Craig Whitney sent a memo to his staff, instructing them not to display any political bumper stickers (or engage in any other activity which showed political preference):
On a recent road trip, I found numerous funny, bittersweet, or just bitter or idiotic political bumper stickers a welcome distraction from $4.50 gas, but also thought I should remind everybody who has anything to do with creating or displaying news content why they shouldn’t display their own political views, on cars or elsewhere, in this campaign season or afterward.
The following two provisions of our Ethical Journalism policy apply:
Journalists have no place on the playing fields of politics. Staff members are entitled to vote, but they must do nothing that might raise questions about their professional neutrality or that of The Times. In particular, they may not campaign for, demonstrate for, or endorse candidates, ballot causes or efforts to enact legislation. They may not wear campaign buttons or themselves display any other insignia of partisan politics. They should recognize that a bumper sticker on the family car or a campaign sign on the lawn may be misread as theirs, no matter who in their household actually placed the sticker or the sign.
Staff members may not themselves give money to, or raise money for, any political candidate or election cause. Given the ease of Internet access to public records of campaign contributors, any political giving by a Times staff member would carry a great risk of feeding a false impression that the paper is taking sides.
Thanks for your cooperation.