The American Association of Retired Persons doesn’t endorse political candidates.  Florida Governor and part-time Trademark Lawyer Jeb Bush sent out a mailing to Florida seniors featuring a picture of him speaking to the AARP, wearing an AARP button and standing in front of an AARP banner.  The AARP has protested the mailer, and says that this mis-leadingly implies that the AARP endorses Bush.  
There is some law on the use of symbols in political speech (see e.g. Brach van Houten Holding v. Save Brach's Coalition, 856 F. Supp. 472, 31 USPQ2d 1786 (ND Ill 1994) (Regarding union’s use of trademark of employer) but on the whole, I wouldn’t say that there is a myriad of decisions on this fact pattern.
 File this with the AFLAC DUCK and the various stupid domain name tricks we’ve seen during this campaign